Importance of concomitant functional mitral regurgitation on survival in severe aortic stenosis patients undergoing aortic valve replacement

BACKGROUND Mitral regurgitation(MR)is commonly seen in patients with severe aortic stenosis(AS)undergoing aortic valve replacement(AVR).But the long-term implications of MR in AS are unknown.AIM To investigate MR’s impact on survival of patients undergoing surgical AVR for severe AS.METHODS Of the 740 consecutive patients with severe AS evaluated between 1993 and 2003,287 underwent AVR forming the study cohort.They were followed up to death or till the end of 2019.Chart reviews were performed for clinical,echocardiographic,and therapeutic data.MR was graded on a 1-4 scale.Mortality data was obtained from chart review and the Social Security Death Index.Survival was analyzed as a function of degree of MR.RESULTS The mean age of the severe AS patients who had AVR(n=287)was 72±13 years,46%women.Over up to 26 years of follow up,there were 201(70%)deaths,giving deep insights into the determinants of survival of severe AS who had AVR.The 5,10 and 20 years survival rates were 75%,45%and 25%respectively.Presence of MR was associated with higher mortality in a graded fashion(P=0.0003).MR was significantly associated with lower left ventricular(LV)ejection fraction and larger LV size.Impact of MR on mortality was partially mediated through lower LV ejection fraction and larger LV size.By Cox regression,MR,lower ejection fraction(EF)and larger LV end-systolic dimension were independent predictors of higher mortality(χ^(2)=33.2).CONCLUSION Presence of greater than 2+MR in patients with severe AS is independently associated with reduced survival in surgically managed patients,an effect incremental to reduced EF and larger LV size.We suggest that aortic valve intervention should be considered in severe AS patients when>2+MR occurs irrespective of EF or symptoms.

Predictors of persistence of functional mitral regurgitation after cardiac resynchronization therapy:Review of literature

Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies.The presence of moderate or severe mitral regurgitation is associated with higher morbidity and mortality.Heart failure patients meeting electrocardiogram and left ventricle function criteria are good candidates for cardiac resynchronization therapy,which may reduce the degree of functional mitral regurgitation in the short and long term,specifically targeting myocardial dyssynchrony and inducing left ventricle reverse remodeling.In this article,we analyze data from the literature about predictors of mitral regurgitation improvement after cardiac resynchronization therapy implantation.

Catheter-based intervention for symptomatic patient with severe mitral regurgitation and very poor left ventricular systolic function-Safe but no room for complacency

Many patients with left ventricular systolic dysfunction have concomitant mitral regurgitation(MR). Their symptoms and prognosis worsen with increasing severity of MR. Percutaneous Mitra Clip® can be used safely to reduce the severity of MR even in patients with advanced heart failure and is associated with improved symptoms, quality of life and exercise tolerance. However, a few patients with very poor left ventricular systolic function may experience significant haemodynamic disturbance in the peri-procedural period. We present three such patients, highlighting some of the potential problems encountered and discuss their possible pathophysiological mechanisms and safety measures.

A Rare Case of Improved Mitral Regurgitation after the Inter-Atrial Septal Defect Created during an Unsuccessful Percutaneous Mitra-Clip Placement Attempt

Percutaneous mitral valve repair has shown to be a less-invasive treatment option for patients with symptomatic severe mitral regurgitation (MR) with multiple comorbidities. We describe a case of improved mitral regurgitation due to improved atrial fibrillation secondary to left atrial pressure relief after the inter-atrial defect created during an unsuccessful mitraclip placement attempt. Transthoracic Echocardiogram that was performed on admission showed severe mitral valve regurgitation. She was not a surgical candidate due to multiple co-morbidities. Patient was then medically optimized and a percutaneous MitraClip placement (PMCP) was attempted but was unsuccessful due to excessive trans-mitral gradient and the procedure was aborted. However, left atrial pressure decreased, likely secondary to inter-atrial septal defect created by the procedure. Transesophageal echocardiogram performed post-op showed moderate and improved mitral regurgitation and sinus rhythm. Attempts to convert atrial fibrillation to sinus rhythm to improve mitral regurgitation had to be made before continuing with a mitral clip placement procedure in our case. In our case, the procedure itself did not help patient’s symptoms, but the resulting acute atrial pressure relief improved mitral regurgitation overall due to left to right shunt from iASD, which also helped the rhythm.

Papillary Muscle Relocation in Secondary Mitral Regurgitation: Midterm Outcomes

Background: Mitral valve repair in secondary mitral regurgitation is still uncertain as the chance of recurrence is approximately 30 percent after solely undersized annuloplasty. Some procedures adding to the subvalvular level are proposed to alleviate the recurrent rate. This study was to evaluate the clinical and echocardiographic outcomes of papillary muscle relocation plus undersized ring in secondary mitral regurgitation (2nd MR). Methods: Medical records of moderate to severe 2nd MR with tethering depth of more than 1 cm patients who underwent papillary muscle relocation plus undersized ring from 2014 to 2020 were reviewed. Clinical and echocardiographic parameters before and after operation were analyzed. Results: Thirty-two patients were included during the 6-year period. There was no perioperative mortality. Two patients died at one year from ischemic stroke and car accidents with overall 5-year survival of 93.7%. All patients were in NYHA class I and II with MR grading as trivial or mild at a median follow-up of 33 months. Postoperative mean tenting depth, area and posterior leaflet angle decreased remarkably from 1.18 cm, 2.61 cm2 and 46.5 degree to 0.65 cm, 1.22 cm2 and 28.6 degree, respectively (p 0.001, 0.02, and 0.01). Moreover, left ventricular function and remodeling were also notably improved (EF;38.2% vs 49.1%: p = 0.018, LVEDD;62.8 vs 54.6 mm: p = 0.005, LVESD;50.2 vs 42.4 mm: p = 0.01). Conclusions: Papillary muscle relocation combined with undersized annuloplasty improved mid-term clinical outcomes. Apart from reduction of recurrent MR rate, restoration of mitral configuration and reverse LV remodeling could be the effect of adding subvalvular correction in this pathology.

Asymptomatic Mitral Regurgitation Caused by an Isolated Mitral Leaflet Cleft in a Young Adult: A Case Report

We report the case of an 18-year-old young man without previous medical history, who was referred for evaluation of an asymptomatic cardiac murmur. Physical examination found holosystolic 4-5/6 apical murmur with normal ECG. Bidimensionnal (2D) echocardiography revealed severe mitral regurgitation with thin mitral leaflets. Three dimensional (3D) Echocardiography done for better assessment of mitral valve regurgitation mechanism revealed an isolated mitral leaflet cleft, without signs of endocarditis or traumatic lesion. Regarding the absence of symptoms and excellent maximal exercise tolerance at stress echocardiography, a repair surgery wasn’t offered. Isolated mitral leaflet cleft is a rare congenital anomaly, in adults, the cleft may be an incidental finding that remains asymptomatic for years when the leak is well tolerated. 2D combined with 3D echocardiography is key for diagnosis and surgery guidance.

The Structural Impact of Aortic Valve Replacement on Mitral Regurgitation

Background: Structural changes to the mitral annulus occur following aortic valve replacement (AVR) for severe aortic stenosis which may influence functional mitral regurgitation (MR). Methods: A retrospective review of 44 patients who underwent open AVR for aortic stenosis at a single center from 2010-2013 was performed. Patients undergoing concomitant aortic root surgery or with severe MR were excluded. MR was evaluated with preoperative and postoperative transthoracic echocardiograms. Univariate and multivariable analyses were performed to assess for factors associated with postoperative MR improvement and worsening. Results: Prior to AVR, none had severe MR, 5% (2 patients) had moderate, 9% (4 patients) mild-to-moderate, 46% (20 patients) mild, and 23% (9 patients) trace MR. Of patients with pre-operative MR, 44% (16 patients) experienced improvement of MR. Six patients had worsening of MR and the remaining 22 patients had no change. Cases of more severe MR were more likely to improve compared with mild or trace MR (P = 0.04). MR worsening was significantly more likely in patients with bicuspid aortic valves (83% vs. 24%;P = 0.004), and with larger aortic annulus diameters (P = 0.03). MR worsening was less frequent in cases of mitral annular calcification (0% vs 42%;P = 0.04) and left atrial enlargement (17% vs 65%;P = 0.03). Logistic regression analysis revealed negative predictors for MR improvement were mitral annular calcification (P = 0.04) and larger aortic annulus diastolic diameter (P = 0.05). Conclusion: Structural factors such as aortic annular size, mitral annular calcification and valve morphology may impact MR following AVR and should be investigated further as potential targets of surgical therapy.

Echocardiographic Follow-up of Robotic Mitral Valve Repair for Mitral Regurgitation due to Degenerative Disease

Background： Mitral valve （MV） repair can now be carried out through small incisions with the use of robotic assistance. Previous reports have demonstrated the excellent clinical result of robotic MV repair for degenerative mitral regurgitation （MR）. However, there has been limited infomlation regarding tile echocardiographic follow-up of these patients. The present study was therefore to evaluate the echocardiographic follow-up outcomes after robotic MV repair in patients with MR due to degenerative disease of the MV. Methods： A retrospective analysis was undertaken using data from the echocardiographic database of our department. Between March 2007 and February 2015, 84 patients with degenerative MR underwent robotic MV repair. The repair techniques included leaflet resection in 67 patients （79.8%）, artificial chordae in 20 （23.8%）, and ring annuloplasty in 79 （94.1%）. Eighty-one （96.4%） of the 84 patients were eligible for echocardiographic follow-up assessment, and no patients were lost to follow-up. Results： At a median echocardiographic follow-up of 36.0 months （interquartile range 14.3-59.4 months）, lbur patients （4.9%） developed recurrent mild MR, and no patients had more than mild MR. Mean MR grade, leli atrial diameter （LAD）, left ventricular end-diastolic diameter （LVEDD）, and let1 ventricular ejection fraction （LVEF） were significantly decreased when compared with preoperative values. Mean MR grade decreased from 3.96 ± 0.13 to 0.17 ± 0.49 （Z- -8.456, P 〈 0.001 ）, LAD from 43.8 ± 5.9 to 35.5 ± 3.8 mm （I - 15.131, P 〈 0.001 ）, LVEDD fiom 51.0 ± 5.0 to 43.3 ± 2.2 mm （t = 14.481, P 〈 0.001 ）, and LV EF l＇rom 67.3 ± 7.0% to 63.9 ± 5.1% （t = 4.585, P 〈 0.001 ）. Conclusion： Robotic MV repair for MR due to degenerative disease is associated with a low rate of recurrent MR, and a significant improvement in MR grade, LAD, and LVEDD, but a significant decrease in LVEF at echocardiographic follow-up.

Comparison of the Outcomes of Modified Artificial Chordae Technique for Mitral Regurgitation through Right Minithoracotomy or Median Sternotomy

Background： Right minithoracotomy （RM） has been proven to be a sate and effective approach for mitral valve surgery, but the differences of artificial chordae technique between RM and median sternotomy （MS） were seldom reported. Here, we compared the outcomes of modified artificial chordae technique for mitral regurgitation （MR） through RM or MS approaches. Methods： One hundred and eighteen consecutive adult patients who received mitral valve repair with artificial chordae and annuloplasty for MR through RM （n = 58） or MS （n = 60） from January 2006 to January 2015 were analyzed. Results： All of the selected patients underwent mitral valve repair successfully without any complication during the surgery. There was no significant difference between RM group and MS group in cardiopuhnonary bypass time, aortic cross-clamp time, and early postoperative complications. However, compared with the MS group, the RM group had shorter hospital stay and taster surgical recovery. At a mean follow-up of 44.8 ± 25.0 months, the freedom from more than moderate MR was 93.9% ± 3.5% in RM group and 94.8% ± 2.9% in MS group at 3 years postoperatively. Log-rank test showed that there was no significant difference in the freedom from recurrent significant MR between the two groups （Х^2= 0.247, P = 0.619）. Multivariate analysis revealed that the presence of mild MR at discharge was the independent risk factor for the recurrent significant MR. Conclusion： Right minithoracotomy can achieve the similar therapeutic effects with MS for the patients who received modified artificial chordae technique for treating MR.

Development in mechanisms of ischemic mitral regurgitation

Objective The clinical diagnosis and treatment of ischemia mitral regurgitation （IMR） remained difficult because of its unclear mechanisms. This paper reviews studies on the mechanisms of IMR during the last 20 years, and discusses the relevance of the various mechanisms. Data sources Data used in this review were mainly from CNKI and Pubmed in English. The search terms were ＂ischemia mitral regurgitation mechanism＂, ＂myocardial infarction＂ AND ＂mitral regurgitation＂. Study selection Articles were selected if they involved mechanisms of IMR. Results IMR is one of the common complications of coronary artery disease. But currently, the clinical diagnosis and treatment of IMR remained difficult because of its unclear mechanisms. Conclusions For now, dominating theory of ischemic mitral regurgitation mechanisms are left ventricular remodeling, imbalance of leaflet tethering and the closing force, left ventricular dysfunction, changes in spatial structure of the annulus and the dyssynchrony of the left ventricular electromechanical activity.

Mitral valve cleft gapping mechanism in functional mitral regurgitation:An in-vitro study

Background and aim:Gapping formation of the mitral valve cleft is unknown.The objective of this study was to quantify the geometry of mitral valve cleft coaptation in the asymmetric and symmetric papillary muscles(PMs)positions in a dilated annulus in order to reveal mitral valve gapping mechanism.Methods:Nine fresh porcine mitral valves with the posterior leaflet clefts were sutured onto a saddle-shaped dilated annulus in an in-vitro experiment to simulate mitral valve closure at hydrostatic pressure.PMs were adjusted to the normal position,and subsequently to positions of asymmetric and symmetric PM displacement.Sonomicrometry was used to measure positions of the lateral and medial clefts.Results:PM displacement tethered the leaflets.Both the opening angle and contact angle of the lateral cleft,but not of the medial cleft,increased in the asymmetric PM displacement.Neither the opening angle nor contact angle of both clefts increased in the symmetric PM displacement.Conclusions:Displacement of the postero-medial PM moves the posterior leaflet medially and impairs coaptation of the lateral cleft,but not medial cleft,which suggest that the medial cleft displacement in the asymmetric PM position is another mechanism of gap formation in addition to leaflet tenting due to apical leaflet displacement.Symmetric PM displacement cause leaflet tenting,but doesn’t impair the leaflet cleft coaptation,which suggest that the asymmetric PM position is even worse than the symmetric PM position.

Functional mitral regurgitation combined with increased early diastolic transmitral velocity to early mitral annulus diastolic velocity ratio is associated with a poor prognosis in patients with shock

Background:Functional mitral regurgitation(FMR)is common in critically ill patients and may cause left atrial(LA)pressure elevation.This study aims to explore the prognostic impact of synergistic LA pressure elevation and FMR in patients with shock.Methods:We retrospectively screened 130 consecutive patients of 175 patients with shock from April 2016 to June 2017.The incidence and impact of FMR and early diastolic transmitral velocity to early mitral annulus diastolic velocity ratio(E/e’)≥4 within 6 h of shock on the prognosis of patients were evaluated.Finally,the synergistic effect of FMR and E/e’were assessed by combination,grouping,and trend analyses.Results:Forty-four patients(33.8%)had FMR,and 15 patients(11.5%)had E/e’elevation.A multivariate analysis revealed FMR and E/e’as independent correlated factors for 28-day mortality(P=0.043 and 0.028,respectively).The Kaplan-Meier survival analysis revealed a significant difference in survival between patients with and without FMR(χ2=7.672,P=0.006)and between the E/e’≥14 and E/e’<14 groups(χ2=19.351,P<0.010).Twenty-eight-day mortality was significantly different among the four groups(χ2=30.141,P<0.010).The risk of 28-day mortality was significantly higher in group 4(E/e’≥14 with FMR)compared with groups 1(E/e’<14 without FMR)and 2(E/e’<14 with FMR)(P=0.001 and 0.046,respectively).Conclusions:Patients with shock can be identified by the presence of FMR.FMR and E/e’are independent risk factors for a poor prognosis in these patients,and prognosis is worst when FMR and E/e’≥14 are present.It may be possible to improve prognosis by reducing LA pressure and E/e’.Trial Registration:ClinicalTrials.gov,NCT03082326.

One-year outcome of percutaneous mitral valve repair in patients with severe symptomatic mitral valve regurgitation

AIM To investigate one-year outcomes after percutaneous mitral valve repair with Mitra Clip~? in patients with severe mitral regurgitation(MR). METHODS Our study investigated consecutive patients with symptomatic severe MR who underwent Mitra Clip~?implantation at the University Hospital Bergmannsheil from 2012 to 2014. The primary study end-point was all-cause mortality. Secondary end-points were degree of MR and functional status after percutaneous mitral valve repair.RESULTS The study population consisted of 46 consecutive patients(mean logistic Euro SCORE 32% ± 21%). The degree of MR decreased significantly(severe MR before Mitra Clip~? 100% vs after Mitra Clip~? 13%; P < 0.001),and the NYHA functional classes improved(NYHA III/IV before Mitra Clip~? 98% vs after Mitra Clip~? 35%; P < 0.001). The mortality rates 30 d and one year after percutaneous mitral valve repair were 4.3% and 19.5%,respectively. During the follow-up of 473 ± 274 d,11 patients died(90% due to cardiovascular death). A preprocedural plasma B-type natriuretic peptide level > 817 pg/m L was associated with all-cause mortality(hazard ratio,6.074; 95%CI: 1.257-29.239; P = 0.012).CONCLUSION Percutaneous mitral valve repair with Mitra Clip~? has positive effects on hemodynamics and symptoms. Despite the study patients' multiple comorbidities and extremely high operative risk,one-year outcomes after Mitra Clip~? are favorable. Elevated B-type natriuretic peptide levels indicate poorer mid-term survival.

Mitral Valve Surgery for Functional Regurgitation: Insights into Heart Failure and Readmission

Background: Functional mitral regurgitation (FMR) is an increasing burden as population ages. Mitral valve repair (MVr) is the preferred surgical treatment of FMR despite limited evidence supporting its efficacy. Mitral valve replacement (MVR) is the alternative procedure typically reserved for patients who are at higher risk or refractory to MVr. The present study aims to determine which of the two procedures is more effective in the surgical treatment of FMR. Methods: 344 charts of FMR patients who received either MVr (n = 263) or MVR (n = 81) from 2004-2016 at our institution were reviewed. Treatment efficacy was assessed based on heart failure (HF)-readmission and survival rates within 5 years from discharge. Propensity score approach with inverse probability weighting and Cox regression models were employed to evaluate procedural impact on survival and rehospitalizations, respectively. Follow-up echocardiographic data from the original cohort was assessed for differences in metrics between procedural groups at >6 months (MVr: n = 75;MVR: n = 23) and 1 year (MVr: n = 75;MVR: n = 18) post-op. Results: MVR patients had a lower risk of being readmitted for HF within 5 years compared to the MVr group (HR-adj (95% CI): 0.60 (0.41 - 0.88), p = 0.008). MVR patients also had a higher overall risk of death (HR-adj (95% CI): 1.82 (1.05 - 3.16), p = 0.034) but this was borderline significantly different at 5 years cut-off (p = 0.057). Conclusions: Higher HF readmission in MVr patients than in sicker, higher surgical-risk MVR patients reflects the inadequacy of MVr to treat FMR. Novel approaches to MVR may be necessary to adequately manage FMR.

Early variation of left ventricular dimension and mitral regurgitation after correction for anomalous origin of the left coronary artery from the pulmonary artery

Background Anomalous origin of the left coronary artery cardiac lesion resulting in myocardial ischemia even infarction, from the pulmonary artery is a rare congenital morphological impairment and dysfunction of left ventricle, together with mitral regurgitation. Here we will introduce our experience in the surgical repair of this kind of congenital lesion and the retrospective analysis about the improvement of left ventricular dimension and mitral regurgitation in early postoperative term. Method From May 1998 to July 2012, 38 consecutive patients with anomalous coronary artery from the pulmonary artery underwent surgical correction （33 received left coronary artery re-implantation, 4 left coronary artery ligation or primary closure, 1 Takeuchi procedure, and 10 simultaneous mitral valve plasty）. Left ventricular dimension, mitral regurgitation, and ejection fraction, were measured by color Doppler echocardiography preoperatively, and 1 month after discharge. Results Hospital survival was 94.7% （2 in-hospital deaths）. Ten paptients with more than moderate mitral regurgitation received simultaneous mitral plasty, one of whom was converted to mechanical prosthetic valve replacement. Mitral valve annuloplasty was applied in 9 cases of coronary re-implantation correction, 3 of whom also received additional mitral leaflet cleft repair. Meanwhile 8 patients underwent other different concomitant operations. Echocardiographic results for the survivals 1 month after discharge showed that left ventricular end-diastolic, endsystolic dimension decreased from 40.05 ± 5.56 mm and 28.94 ± 6.21 mm to 33.07 ± 6.82 mr, （P 〈 0.01） and 23.04 ±5.87 mm （P 〈 0.01） respectively. The average mitral regurgitation grade was also reduced from 2.36 ± 1.08 to 1.64 ± 93 （P 〈 0.05） in the group. All survival patients improved clinically and NYHA functional class decreased significantly from 2.37 ± 1.08 to 2.10 ±0.54 （P 〈 0.05）. Conclusions The surgical repair of anomalous origin of the left coronary artery from the pulmonary artery is safe and effective, and can get satisfactory dimensional and functional improvement of the left ventricle in early term. Although controversial, concomitant mitral valve plasty can be helpful for critical patients with severe mitral regurgitation.

Echocardiographic and clinical outcomes of central versus non-central percutaneous edge-toedge repair of degenerative mitral regurgitation

ABSTRACT Objectives We aimed to assess the clinical and echocardiographic results of MitraClip implantation in non-central de- generative mitralregurgitation （dMR） compared to central dMR. Background It is unknown if the use of the MitraClip therapy in non-central dMR is as safe and effective as in central dMR.

A Procedure of Combination of Sequential Internal Thoracic Artery Grafting and Cooley's Technique for Complicated Case With Multi-vessel Disease,Left Ventricular Aneurysm and Mitral Regurgitation

INTRODUCTIONLeft ventricular aneurysm and ischemic mitral regurgitation are two of most common complications of acute myocardial infarction （AMI）. Combination of both these two fatal complications is not rare and the management of these complicated cases is always a challenge to cardiac surgeon because of its relatively high mortality. We reported a rare case of AMI in which a singlestage correction of mitral valve replacement with preservation of mitral apparatus, sequential left internal thoracic artery （ITA） grafting and Cooley＇s technique.

Thirty-day Outcomes of First-in-man Implantation of a Novel Transcatheter Edge-to-edge Mitral Repair System in Patients With Severe Mitral Regurgitation

Objectives:The aim of this multicenter,prospective,single-arm pilot study(ClinicalTrials.gov number:NCT05040074)was to observe the procedural and 30-day results of the novel transcatheter mitral valve repair system,SQ-Kyrin■-M Clip(Shenqi Medical,Shanghai,China),in patients with severe mitral regurgitation(MR).Methods:The heart team considered patients from 5 centers in China with clinically significant functional mitral regurgitation≥3+despite optimal medical therapy or degenerative mitral regurgitation≥3+with high surgical risk as candidates for transcatheter repair.All patients received transcatheter edge-to-edge mitral valve repair under general anesthesia.The primary outcome was technical success,which included all of the following measured at the exit from the catheterization laboratory:(1)absence of procedural mortality;(2)successful access,delivery,and retrieval of the device delivery system;(3)successful deployment and correct positioning of the frst intended device;and(4)no emergency surgery or reintervention related to the device or access procedure.The secondary outcomes included all-cause mortality,serious adverse events,device success,and procedural success 30 d after the intervention.Results:From June 2021 to December 2021,18 patients were enrolled in this study with age(75.7±7.4)years.Fifteen patients had MR 4+,while 3 had MR 3+.Technical success was achieved in all patients,including 6 degenerative mitral regurgitation and 12 functional mitral regurgitation patients.There was no all-cause mortality at 30 d.One patient had single leaflet device attachment within 30 d,which was regarded as a serious adverse event,and the patient was successfully treated with reintervention by implanting another clip.Another patient's transmitral gradient was 6 mmHg(>5 mmHg),with an effective orifice area of 2.57 cm^(2) after the procedure.Sixteen patients had device success and procedural success at 30 d postoperation.Fourteen patients had MR 1+,3 had MR 2+,and only 1 patient had MR 3+30 d after the procedure.Conclusions:The results of this feasibility study showed the efficacy and safety of the SQ-Kyrin■-M device in the Chinese population with severe MR,laying a solid foundation for a subsequent large-scale confirmatory study.

Transcatheter mitral valve implantation using a novel system:preclinical results

Background This preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system(Mi-thos valve)composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.Methods The valve was implanted in 26 sheep using a transapical approach for short-and long-term evaluation.The technical feasibility,safety,durability,and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography,multisliced computed tomography,histological analysis,and electron microscopy.Results The success rate of valve implantation was 100%,and the immediate survival rate after surgery was 84%.Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction(n=2)and sudden intraoperative ventricular fibrillation(n=3).Twelve animals died within 1 month due to acute left heart dysfunction.Mild(n=5)and moderate(n=2)paravalvular leakage occurred in seven animals,and two moderate PVL animals died of chronic heart failure within three months.Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves,with no coronary artery obstruction,no left ventricular outflow tract obstruction,no severe transvalvular gradients and no paravalvular leakage.Macroscopic evaluation demonstrated stable,secure positioning of the valve,with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls.Histological and electron microscopic examinations at six months showed no obvious macro-or microcalcification in the leaflets.Conclusions Preclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible.The durability,functionality,and lack of leaflet calcification were all verified in animal experiments.The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.

Anterior Mitral Valve Orifice in a Dog

The patient was admitted to OndokuzMayıs University Animal Hospital Internal Medicine outpatient clinic with complaints of epileptic seizures and hypothyroidism. A description of the patient’s owner is available in the history information. There was no physician information. Bradycardia was found in the electrocardiography of the patient. 2-D, M-Mode, PW, CW and Color doppler examinations were performed. Left-ventricular hypokinetic and mitral and tricuspidal valve movements were observed with limited M-Mode imaging. Anterior mitral orifice of 2 mm width was detected on septal mitral valve by PW doppler and color doppler. With this orifice, the presence of regurgitant jet, which covers LA at a rate of 1/3 and was 3.2 m/sec, together with mitral regurgitation (0.5 m/sec.), was demonstrated. PISA calculations;VFR (mL/s), ERO (mm2) and RVol (mL/pulse) values were calculated as if there were mitral regurgitation and data were obtained for mild-moderate mitral regurgitation. Therefore, no operative treatment of the orifice was recommended. Mitral valve orifice is a rare pathology and this is the first report in canine veterinary practice with degenerative mitral valve disorder. We aimed to underline the possibility of mitral orifice development in degenerative mitral valve disorders, known to present with vegetations and varying degrees of prolapsus, conventionally.