Tips and tricks of left main artery stenting

Left main coronary artery stenosis traditionally resided ,exclusively in the realm of coronary artery bypass grafting surgery （CABG） as a means of revascularization. Due to growing evidence in the literature, including multiple recent registries and even some randomized controlled trials showing similar rates of major adverse outcomes for CABG and left main artery percutaneous coronary intervention （PCI）, there is increased interest in and even an upgraded status in current guidelines for left main PCI as a viable option for left main revascularization.

Off-pump versus on-pump coronary artery bypass surgery for the treatment of left main with triple coronary artery disease

Objective：To obtain early results of off-pump coronarE~ artery bypass grafting（OPCAB） in patients with significant left main coronary artery（LMCA） and triple vessels stenosis by comparing with those of a similar group undergoing conventional coronary artery bypass surgery（CCAB）. Methods：Data for patients with significant LMCA and triple vessels stenosis who underwent CCAB or OPCAB were collected retrospectively between January 1999 and May 2006. Non-randomized, retrospective data analysis included demo- graphic and preoperative risk factors, operative details, clinical outcome and early follow-up. Results： The number of distal anastomo- sis and grafts varied from 3 to 6. The average number per patient was similar in the two groups （OPCAB group：3.76 ± 0.98, CCAB group：3.81 ± 1.02）. Thirty-day mortality occurred to one patient in the OPCAB group whereas two early deaths were observed in the CCAB group but did not reach statistical significance （P 〉 0.05）. The frequency of atrial fibrillation （AF）, IABP usage, mediastinitis, re-operation for bleeding （or tamponade） were similar in the two groups （P 〉 0.05）. Postoperative inotropic requirements, peak CKMB, ventilation time, blood loss, FFP, RBC transfusion need and the length of ICU-stay were all significantly lower in the OPCAB group compared with CCAB group（P 〈 0.05）.Conclusion： Significant LMCA and triple-vessel stenosis can safely and effectively undergo myocardial revascularization using OPCAB surgery. LMCA should no longer be seen as a contraindication to perform OPCAB grafting.

Therapeutic effect of interventional therapy for unprotected left main coronary artery lesions in aged patients

Objective To assesse the therapeutic effect of interventional therapy in aged patients with unprotected left main coronary artery （UPLM） lesions. Methods A total of 61 patients who were over 60 years and accepted interventional therapy of UPLM from January 2012 to November 2013 in our hospital were followed up for average 14.6 months by telephone call or outpatient visits. We analyzed the clinical features data of the interventional therapy and assessed the factors that likely influenced the clinical prognosis. Results The average age of the 61 patients was 73.9 years. The average left ventricular ejection fraction （LVEF） was 47.7%. The median of the estimated glomerular filtration rate （eGFR） was 52 mL/min per 1.73 mmz. The average SYNTAX score was 27.4 and the median of stent length was 36 mm. The cumulative incidence of cardiac death at 30 days and major adverse cardiac events （MACE） after one year was 6.6% and 32.5% estimated by Kaplan-Meier plots respectively. No severe hemorrhagic complications were observed during follow-up period. On multivariate regression analysis with a COX proportional hazards model, LVEF was an independent predictor of cardiac death at 30 days [Hazard ratio （HR）： 0.7, P = 0.01]. As for MACE after one year, LVEF and eGFR were both independent predictors （HR： 0.91, P = 0.06 for LVEF, HR： 0.03, P = 0.097 for eGFR）. Conclusions The interventional therapy for UPLM was effective and safe in aged patients. LVEF was the only predictor of cardiac death at 30 days, while LVEF and eGFR were both independent predictors of MACE after one year.

How much can be inferred from the left main coronary artery?

Atherosclerotic diseases is a diffuse process that involves the coronaries, carotids, renals and all other peripheral arteries owing to the systemic nature of atherosclerotic pathophysiology. This systemic precipitants that promote aggressive atherogenesis have been confirmed in multiple studies showing a relationship between atherosclerotic disease in one vascular bed with disease in another. However, the strength of this relationship varies from patient to patient. Thus, the practical utility of the diffuse nature of atheresclerosis is questionable. Ge and colleagues have proposed the use of left main (LM)coronary artery disease as a potential marker for left anterior descending (lAD) atherosclerotic disease. At first thought, this seems useless since the evaluation of the LM (by angiography or IVUS) can just as easily be performed in the LAD so why bother searching for such a surrogate? However, newer (non-invasive) imaging modalifies are making great gains and will be able to reliably image the LM sooner than the LAD (especially the distal LAD) so such a surrogate could have practical applications.

A Case Summary of the Application of a Drug-eluting Stent Combined with a Drug-Coated Balloon in Left Main Coronary Artery Disease

Objective:To evaluate the clinical efficacy of a drug-eluting stent(DES)combined with a drug-coated balloon(DCB)in the treatment of left main coronary artery bifurcation lesions.Methods:A retrospective analysis was conducted on the clinical data of eight patients with left main coronary artery bifurcation lesions treated with a DES combined with a DCB who were admitted to our hospital from July 2016 to July 2017.These eight patients all underwent DES treatment for their left main coronary artery and left anterior descending coronary artery lesions,and DCB treatment at the ostium of the left circumflex artery;six of the patients underwent surgical procedures under the guidance of intravascular ultrasonography.Immediate postoperative angiography was used to evaluate the patency of the diseased vessels,and the restenosis rate at the 6-month follow-up after the operation and the incidence of serious clinical events within 6 months were assessed as well.Results:The use of a DES combined with a DCB in the treatment of left main coronary artery bifurcation lesions had a low restenosis rate(left main coronary artery(8.4±5.3)%,left anterior descending coronary artery(18.2±5.0)%,left circumflex artery(30.5±16.5)%).No serious clinical events occurred in any patients.Conclusion:A DES combined with a DCB is a safe and effective interventional treatment for left main artery coro-nary bifurcation lesions.

Iatrogenic Disruption of Left Main Coronary Artery during Aortic Valve Replacement

This aortic valve replacement (AVR) remains the gold standard for symptomatic aortic stenosis. Peri-operative complications like dissection, stenosis involving coronary artery are well described in many series. We present a rare iatrogenic complication of disrupted left main coronary artery during the delivery of cardioplegia while performing AVR in a 54 year male patient for severe calcific aortic stenosis. The inadvertent injury to the artery was timely noticed and managed successfully with long saphenous vein graft.

Transcatheter aortic valve replacement(TAVR) for severe aortic valve stenosis with left main artery disease:A case report

Introduction: This is the first case of Transcatheter Aortic Valve Replacement(TAVR) in the prefecture level hospital of Xinjiang Province in China. It also proves that severe left main coronary artery disease(LM)is not the contraindication to this operation of TAVR. Patient concerns:The patient had dyspnea for two years, with the 4/6 spurious murmur at the aortic valve. The cardiac ultrasound revealed a severe aortic valve stenosis(AS) and severe mitral regurgitation(MR). Coronary angiography(CAG)showed 80% stenosis of the left main artery. Diagnosis: The severe aortic valve stenosis(AS). Interventions: He received the TAVR, which also is the first case in the First People's Hospital of Kashi Prefecture. Outcomes: The patient's symptoms were significantly improved. The cardiac ultrasound showed that no obvious regurgitation was found in the implanted artificial aortic valve and the MR was significantly reduced. So far, the patient has recovered well for five months after TAVR. Conclusion:TAVR is an effective method for the severe AS patients with serve LM and loss of surgical opportunity.

Undifferentiated intimal sarcoma of the pulmonary artery:A case report

BACKGROUND Since 1923,only a few hundred cases of pulmonary arterial sarcoma(PAS)have been reported.It is easy for PAS to be misdiagnosed as pulmonary thromboembolism,which makes treatment difficult.The median survival time without surgical treatment for PAS is only 1.5-3 mo.Echocardiography is widely used in screening for pulmonary artery space-occupying lesions in patients with chest pain,dyspnea,and cough;furthermore,it is typically considered the first imaging examination for patients with PAS.CASE SUMMARY In May 2017,a 39-year-old male patient experienced chest pain with no particular obvious cause.At that time,the cause was thought to be pulmonary embolism.In July 2017,positron emission tomography–computed tomography revealed spaceoccupying lesions in the right lung and multiple metastases in both lungs.The lesions of the right lung were biopsied,and pathology revealed undifferentiated sarcoma.Chemotherapy had been performed since July 2017 in another hospital.In December 2019,the patient was admitted to our hospital for the sake of CyberKnife treatment.Echocardiography suggested:(1)A right ventricular outflow tract(RVOT)solid mass of the main pulmonary artery;and(2)mild pulmonary valve regurgitation.Ultrasonography showed the absence of a thrombus in the deep veins of either lower limb.CONCLUSION PAS is a single,central space-occupying lesion involving the RVOT and pulmonary valve.Echocardiography of PAS has its own characteristics.

PROGNOSIS OF UNPROTECTED LEFT MAIN CORONARY ARTERY STENTING AND THE FACTORS AFFECTING THE OUTCOMES IN CHINESE

Background The long term prognosis of unprotected left main coronary artery （LMCA） stenting is controversial This study was conducted to evaluate the immediate and long term outcomes of LMCA stenting in Chinese patients and to determine which factors affect the outcomes. Methods From May 1997 to March 2003, 224 patients in 23 hospitals underwent elective unprotected LMCA stenting with bare metal stents. Their clinical records were analysed to ascertain immediate and long term outcomes of LMCA stenting as well as factors influencing the prognosis. Results Stents were implanted into LMCA successfully in 223 cases （99.6 %）. One death （0.5%） and one case of non-Q wave nonfatal myocardial infarction （MI） occurred in hospital. The mean follow-up time was （15.6±12.3） months. Cardiac death developed in 10 cases （4.5%）, noncardiac death in 2 cases （0.9%）, nonfatal MI in 4 cases （1.8%）, target lesion revascularization （TLR） of LMCA in 26 cases （11.7%） and TLR of nonLMCA in 37 cases （16.5%）. Univariate analysis showed that cardiac death correlated with left ventricular ejection fraction （LVEF 〈 40%）, female gender and LMCA combined with multivessel disease; that major adverse cardiac events （MACE） correlated with LVEF 〈 40%, bifurcation lesion and incomplete revascularization. Logistic regression analysis revealed that LVEF 〈 40% and female gender were independent predictors of cardiac death and MACE. Follow-up angiography was performed in 102 cases （45.7%）. The restenosis rate was 31.4%. Conclusions Long-term outcomes of stenting for selected patients with unprotected LMCA stenosis is acceptable. It should be performed in inoperable or low risk patients with LVEF ≥40% and isolated LMCA disease or LMCA combined with multivessel diseases in whom complete revascularization can be obtained.

Efficacy of stenting for unprotected left main coronary artery disease in 297 patients

Background Angioplasty in the unprotected left main coronary artery （LMCA） has been controversial. This study aims to evaluate the safety and clinical effectiveness of stenting, including bare metal stent and drug eluting stent （DES）, for treatment of unprotected LMCA disease. Methods Between September 1997 and December 2005, a total of 297 consecutive patients underwent percutanous coronary intervention （PCI） on LMCA lesions in our hospital. Their in-hospital data and clinical follow-up outcomes were analyzed and those in pre-DES ＂＇era＂ （group I, from September 1997 to December 2002） were compared with those in DES ＂era＂ （group Ⅱ, from January 2003 to December 2004. Patients in 2005 for the time of follow-up less than one year were not included in this group）. Results Altogether 368 coronary stents were successfully deployed in 295 patients. Stents failed to be implanted after balloon predilation in two patients, who received coronary artery bypass graft （CABG） successfully. Bifurcation techniques for distal LMCA executed in 206 patients （69.4%, 2061297）, included crossover stenting in 156 （75.7%）, T stenting in 4 （1.9%）, provisional T stenting in 28 （13.6%）, kissing stenting in 5 （2.4%） and stent crushing in 13 （6.3%） patients. During their hospital stay, 5 （1.7%） patients died after PCI procedure, of which 4 died from cardiac origin and one of renal failure. The total in-hospital major adverse cardiac events （MACE） were 2.0% （6/297）. In the follow-up period, 19 patients （6.5%） died [15 （5.1%） of cardiac death and 4 of non-fatal myocardial infarction （MI）]. Besides, 2 （0.7%） developed subacute thrombosis （SAT） and 16 （5.4%） performed target lesion revascularization （TLR）. The total follow-up MACE was 14.5% （431297）. Further analysis also showed that, compared with patients in group I, those in group II apparently had more multi-vessel involvement （14.7% vs 81.9%, P〈0.001）, and more bifurcation lesions （32.4% vs 72.2%, P〈0.001）. After PCI, in-hospital MACE of group II was significantly lower than that in group I （1.1% vs 9.4%, P〈0.05）. And the incidences of MACE, TLR and angiographic restenosis in group II were all significantly lower than those in group I （all P〈0.05） after one year follow-up. Conclusions As new PCI strategies and intervention devices such as DES are developed, coronary stenting, which might have brought better in-hospital and long-term outcomes than CABG are proved to be technically successful and can be safely applied for the treatment of LMCA lesions in the experienced center for coronary intervention.

One-year Outcomes in Patients with ST-segment Elevation Myocardial Infarction Caused by Unprotected Left Main Coronary Artery Occlusion Treated by Primary Percutaneous Coronary Intervention

Background： Very few data have been reported for ST-segment elevation myocardial infarction （STEMI） caused by unprotected left main coronary artery （ULMCA） occlusion, and very little is known about the results of this subgroup of patients who underwent primary percutaneous coronary intervention （PCI）. The aim of this study was to determine the clinical features and outcomes of patients with STEMI who underwent primary PCI for acute ULMCA occlusion. Methods： From January 2000 to February 2014, 372 patients with STEMI caused by ULMCA acute occlusion （ULMCA-STEMI） who underwent primary PCI at one of two centers were enrolled. The 230 patients with non-ST-segment elevation MI （NSTEMI） caused by ULMCA lesion （U LMCA-NSTEMI） who underwent emergency PCI were designated the control group. The main indexes were the major adverse cardiac events （MACEs） in-hospital, at 1 month, and at 1 year. Results： Compared to the NSTEMI patients, the patients with STEMI had significantly higher rates of Killip class≥Ⅲ （21.2% vs. 3.5%,χ^2= 36.253, P 〈 0.001 ） and cardiac arrest （8.3% vs. 3.5%, χ^2= 5.529, P = 0.019）. For both groups, the proportions of one-year cardiac death in the patients with a post-procedure thrombolysis in myocardial infarction （TIMI） flow grade〈3 were significantly higher than those in the patients with a TIMI flow grade of 3 （STEMI group： 51.7% [ 15/29] vs. 4.1% [ 14/343], P 〈 0.001 ; NSTEM I group： 33.3% [3/9] vs. 13.6% [3/221], P = 0.001; respectively]. Landmark analysis showed that the patients in STEM I group were associated with higher risks of MACE （16.7% vs. 9.1%, P 0.009） and cardiac death （5.4% vs. 1.3%, P- 0.011 ） compared with NSTEMI patients at I month. Meanwhile, in patients with ULMCA, the landmark analysis for incidences of MACE and cardiac death was similar between the STEMI and NSTEMI （all P=0.72） in the intervals of 1-12 months. However, patients who were diagnosed with STEMI or NSTEMI had no significant difference in reinfarction （all P 〉 0.05） and TVR （all P〉 0.05） in the intervals of 0-1 rnonth as well as 1 month to 1 year. The results of Cox regression analysis showed that the differences in the independent predictors for MACE included the variables of Killip class ≥ Ⅲ and intra-aortic balloon pump support for the STEMI patients and the variables of previous MI, ULMCA distal bifurcation, and 2-stent for distal ULMCA lesions for the NSTEMI patients. Conclusions： Compared to the NSTEMI patients, the patients with STEMI and ULMCA lesions still remain at a much higher risk for adverse events at I year, especially on I month. Ira successthl PCI procedure is performed, the 1-year outcomes in those patients might improve.

Quantitative and qualitative assessment of non-obstructive left main coronary artery plaques using 64-multislice computed tomography compared with intravascular ultrasound

Background There are few reports of quantitative and qualitative measuring of left main coronary artery （LMCA） plaques by multislice computed tomography coronary angiography （MSCTA）, especially when compared with intravascular ultrasound （IVUS） as reference standard. The aim of this study was to evaluate the use of 64-MSCTA in the diagnosis of LMCA disease, and the accuracy of MSCTA in the quantitative and qualitative assessment of the LMCA lesion as compared with IVUS.Methods A total of 91 patients （53 men, 38 women, mean age （64.78±9.19） years） were examined by 64-MSCTA and IVUS. Compared with the IVUS, the sensitivity, specificity, positive and negative predictive values （PPV and NPV） of the MSCTA on the diagnosis of LMCA diseases were calculated. Also, kappa index （K） for the agreement between MSCTA and IVUS was calculated. Minimal lumen area （MLA）, external elastic membrane cross-sectional area （EEM-CSA） and plaque burden were measured by two blinded and independent operators on MSCTA cross-sectional reconstruction and compared with the parameters measured from IVUS by manually tracing. The CT value of soft, fibrous and calcific plaques was measured using IVUS classification of the plaques.Results The sensitivity, specificity, PPV and NPV of MSCTA for detecting LMCA plaques were 93.1%, 84.2%, 95.7%, 76.2%, respectively. Kappa index （K=0.744, P〈0.001） indicated excellent agreement between MSCTA and IVUS. The Pearson index between MLA on IVUS and MLA on MSCTA was 0.815 （P 〈0.01）. The Pearson index of plaque burden and EEM-CSA between IVUS and MSCTA was 0.736 and 0.740 respectively （both P 〈0.01）. The CT value of soft plaque, fibrous plaque and calcific plaque compared with IVUS were （52.52±15.71） HU, （108.32±43.44） HU and （604.16±377.67） HU （P〈0.001）. Receiver operating characteristic curve analysis of CT value of non-calcific plaques for predicting soft plaques showed the cutpoint was 54.35 HU, with a sensitivity of 83.3% and specificity of 94.4%. Conclusions Sixty-four section MSCTA is an effective diagnostic tool for the detection of LMCA plaques with higher sensitivity and specificity. The correlation of quantitative and qualitative analysis between MSCTA and IVUS was excellent. The CT value of plaques can help the diagnosis of plaque composition.

Saddle pulmonary embolism is not a sign of high-risk deterioration in non-high-risk patients: A propensity score-matched study

BACKGROUND: There is controversy regarding whether saddle main pulmonary artery(MPA) embolism represents a high risk of deterioration in non-high-risk acute pulmonary embolism(PE) patients. This study aims to address this issue by conducting a propensity score matching(PSM) study.METHODS: A total of 727 non-high-risk acute PE patients were retrospectively evaluated. We evaluated the Bova score and risk stratification to examine the risk of deterioration. Deterioration defined as any adverse event within 30 days after admission. Computed tomographic pulmonary angiography was used to identify the embolism type. All patients were matched into four subgroups by PSM according to age, sex, Bova score, and risk stratification:(1) MPA and non-MPA embolism;(2) non-saddle MPA and non-MPA embolism;(3) saddle MPA and non-saddle MPA embolism;(4) saddle MPA and non-MPA embolism. Correlations were analyzed using Cox regression analysis, and deterioration risk was compared between subgroups using Kaplan-Meier analysis.RESULTS: Cox regression analysis revealed that MPA embolism was correlated with deterioration, regardless of whether saddle MPA embolism was included or excluded. Saddle MPA embolism was not correlated with deterioration, regardless of comparison with non-saddle MPA embolism or non-MPA embolism. Patients with MPA and non-saddle MPA embolism presented a high risk for deterioration(logrank test=5.23 and 4.70, P=0.022 and 0.030, respetively), while patients with saddle MPA embolism were not at a high risk of deterioration(log-rank test=1.20 and 3.17, P=0.729 and 0.077, respetively).CONCLUSIONS: Saddle MPA embolism is not indicative of a high risk of deterioration in nonhigh-risk acute PE patients.

INTRAVASCULAR ULTRASOUND IMAGING OF ANGIOGRAPHICALLY "SILENT" LEFT MAIN CORONARY ARTERY ATHEROSCLEROSIS

Patients with left main coronary artery (LMCA) atherosclerosis have a poor prognosis compared with lesions in the other coronaries. Because of the methodological problems. LMCA atherosclerotic lesions are not frequently detected by coronary angiography. The purpose of the study was to reveal the existence of LMCA disease in patients with normal coronary arteries by using intravascular ultrasound imaging. Ninety-seven patients with angiographically normal coronary arteries were examined with a 3.5 F or 4.8 F. 20 MHz intravascular ultrasound catheter. The vessel, lumen and plaque areas were determined and percent area and diameter stenosis were calculated. Plaque formation with or without calcific deposits identified by ultrasound accoustic shadowing were regarded as signs of atherosclerosis.

Reversible ischemia on treadmill exercise in left main coronary artery vasospasm

Coronary vasospasm of the left main coronary artery （LMCA） is a rare condition with potentially devastating consequences. We present 2 patients with LMCA vasospasm-related angina, the first being a 46-year-old woman and the second a 51-year-old woman. Both of them developed ST-segment ischemic changes on treadmill exercise tests. Coronary angiography showed spontaneous LMCA vasospasm in one patient and methylergonovine-induced LMCA vasospasm in the other patient. Follow-up treadmill exercise tests revealed no exercise-induced ischemia after calcium antagonist monotherapy. These cases demonstrate the importance of identifying LMCA vasospasm, as the treatment of choice varies in patients with angina pectoris. Reversible myocardial ischemia caused by LMCA vasospastic angina can be controlled by calcium antagonist monotherapy and detected by repeat non-invasive stress testing.

Coronary artery anomalies： the left main coronary artery or left anterior descending coronary artery originating from the proximal of right coronary artery

Coronary artery anomalies （CAAs） are present at birth, but are usually asymptomatic and are found during coronary angiography or multi-slice computed tomography （MSCT） examinations. Their prevalence is less than 1.3% based published series.1＇2 The most common coronary anomaly is separate origin of the left anterior descending coronary artery （LAD） and left circumflex coronary artery （LCX） from the left sinus of the Valsalva. The second most common anomaly is the origin of the LCX artery from the right coronary artery （RCA） or right sinus of the Valsalva. We present two cases of coronary artery anomalies： one is the left main coronary artery （LMCA） arising from the proximal RCA, the other is the LAD originating from the proximal RCA.

Stenting for left main stenosis in a child with anomalous origin of left coronary artery: case report

Anomalous left coronary artery ( LCA) arising from right cusp is an uncommon condition. Clinical evidence has shown that this coronary anomaly is consistently related to sudden death. Current treatment options include modification of behaviour, medicine or surgery. Stents have been successfully applied for left main stenosis for a decade. We report a case of LCA arising from right cusp with left main stenosis treated with coronary stent in a child patient.

High volume practice proved the safety of off-pump coronary artery bypass surgery in left main coronary artery lesions： a two-year single center experience

Background Left main coronary artery （LMCA） stenosis has been recognized as a risk factorfor early death among patients undergoing coronary artery bypass grafting （CABG）. This study aimed to assess if LMCA lesions pose an additional risk of early or mid-term mortality and/or a major adverse cardiac and cerebrovascular event （MACCE） after off-pump coronary artery bypass grafting （OPCABG）, compared with non-left main coronary artery stenosis （non-mainstem disease）.

Impact of Coronary Chronic Total Occlusion on Long-term Clinical Outcome in Patients with Unprotected Left Main Disease Undergoing Percutaneous Coronary Intervention

Objectives:Reported data regarding the prevalence,prognostic impact,and safety and efficacy of revascularization of coronary chronic total occlusion(CTO)in patients with left main coronary artery(LMCA)disease who undergo percutaneous coronary intervention(PCI)are scarce.The aim of the present study was to compare clinical outcomes among patients with LMCA disease undergoing PCI.Outcomes were compared between those with and without coronary CTO and between those with CTO who had successful and unsuccessful CTO recanalization procedures.Methods:All consecutive patients with significant LMCA disease(>50%stenosis at coronary angiography)who underwent PCI between July 2014 and December 2018 were retrospectively included in our study.The primary endpoint of the study was long-term mortality.Secondary endpoints included the incidence of myocardial infarction,repeat percutaneous or surgical revascularization,stroke,and stent thrombosis.Results:Between July 2014 and December 2018,578 patients underwent PCI for LMCA disease at Pederzoli Hospital and University of Turin were enrolled.They were divided into 3 groups:group A:374(65%)patients without CTO,group B:108(19%)patients with untreated or unsuccessfully treated CTO,and group C:96(17%)patients with successfully treated CTO.At a median follow-up of(1090±279)days,there were no statistically significant differences between the groups in terms of the primary and secondary endpoints.However,there was a trend towards higher mortality in patients with untreated or unsuccessfully treated CTO(13%vs.19%vs.14%in groups A,B,and C,respectively;P=0.12).The primary and secondary endpoints were further analyzed based on the presence or absence of myocardial viability:subgroup C1:54(56%)patients with successful percutaneous transluminal coronary angioplasty(PTCA)having viability,and subgroup C2:42(44%)patients with successful PTCA not having viability.There was a trend toward a statistically significant higher rate of death among patients in group B,who underwent unsuccessful recanalization with viable myocardium(19%vs.9%vs.19%in groups B,C1,and C2,respectively,P=0.05).On multivariable analysis,the propensity for successful revascularization of CTO was associated with a reduced risk of death(P=0.01;odds ratio,0.75;95%confidence interval:0.62-0.87).Conclusions:Among patients with LMCA disease undergoing PCI,CTO represents a common finding associated with worse prognosis.Successful revascularization of CTO in patients with viable myocardium appears to significantly improve prognosis.