Coronary Artery Stenting in Patients with Severe Left Ventricular Dysfunction

Percutaneous transluminal coronary angioplasty (PTCA) may be an effective treatment in selected patients with left ventricular dysfunction, but acute and long-term mortality rates are higher than in patients with normal left ventricular function.^1–5 Coronary artery stenting improves procedural success rates and reduces restenosis in patients with normal left ventricular function as compared to angioplasty,^7,8 but in patients with depressed left ventricular ejection fraction (EF), the results of stenting have not been widely reported. The goal of this study was to describe our experience with coronary stenting in patients with a left ventricular EF less than or equal to 40%. Methods All 1,187 patients who underwent coronary artery intervention at our institution from July 2001 to June 2003 were prospectively entered into the American College of Cardiology National Cardiovascular Data Registry. We excluded patients for whom coronary intervention was performed as primary therapy for acute ST-elevation myocardial infarction (MI) (n = 208), then excluded patients with no left ventricular angiography at the time of coronary intervention (n = 12, in most cases contraindicated by severe renal insufficiency), then excluded patients with an EF > 40% (n = 784), and finally excluded patients whose intervention did not include an attempt to place a coronary stent (n = 34). The remaining 149 patients were included in this study. In all patients, coronary revascularization was indicated due to presentation with acute coronary syndromes or ischemia on stress imaging studies. Patients who underwent repeat procedures during the follow-up period were not counted twice. Coronary intervention was routinely performed (89% of patients) during the same session as diagnostic coronary angiography and left ventriculography. Patients referred from other institutions for coronary intervention routinely underwent left ventriculography in the same session to confirm left ventricular function. Prophylactic intra-aortic balloon pump support was not used. Drug-eluting stents (DES) were not available during the study period. All coronary interventions were performed by 1 of 3 experienced operators (mean experience: 14 years and > 2,000 interventions). Operators performed multivessel intervention when possible rather than multi-staged procedures. All patients were treated with aspirin indefinitely and clopidogrel for 1–12 months after the intervention. Left ventriculography was performed in the 30 degree right anterior oblique view with standard 4–6 Fr catheters, using 35–40 cc of radiographic contrast. EF was estimated by the interventional operator and was compared to a theoretical normal EF of 65%. Demographic, angiographic, procedural, and angiographic outcome variables for each patient were recorded by the operator immediately after the procedure in standardized data forms for entry into the American College of Cardiology National Cardiovascular Data Registry. Follow-up data on all patients were collected by reviewing office visit and hospital admission records. Using structured telephone interviews, 148 patients (99%) were asked about the occurrence of MI, chest pain, coronary revascularization, congestive heart failure (CHF) and hospitalization since the index PCI. Patients were asked whether cardiac symptoms at the time of interview were improved, similar or worse than at the time of coronary intervention. Results Patients were predominantly male (75%) (Table 1). Past history included congestive heart failure in 33%, previous percutaneous coronary intervention in 43% and previous coronary artery bypass surgery in 31%. Presenting syndrome included stable angina or positive stress testing in 13%, unstable angina in 34%, non-Q wave MI in 45%, and recent Q-wave MI in 8%. The mean left ventricular EF was 35 ± 10 (range 15–40%). Left ventricular EF was 1–5 (Table 3). Di Sciascio, in the stent era, found a major complication rate of 1%.⁶ The absence of major complications in 149 of our study’s patients confirms Di Sciascio’s finding that percutaneous stenting can be performed safely, even in high-risk patients. Clinical success rates ranged from 77–91% in the angioplasty era,^1–5 but Di Sciascio reported a 99% success rate.6 Our finding of 100% clinical success confirms that operators in the era of stents and advanced pharmacologic cotreatments can achieve excellent angiographic outcomes and short-term clinical results. A second important finding of this study is that long-term mortality remains high even after successful coronary intervention. We found an overall mortality of 11% at 24 month follow-up, compared to 6% in the study by Di Sciascio. However, patients in our study had more frequent diabetes (39% versus 14%), more prior CABG (31% versus 6%), and more multivessel coronary disease (80% versus 54%). The mortality of 11% at 24-month follow-up in our study compares favorably to the 15–25% mortality rate at 2- to 3-year follow-up reported in the angioplasty era.^1–5 Prior reports of coronary intervention in patients with severe left ventricular dysfunction have found that noncardiac deaths comprise only 7–35% of all late deaths. We found that noncardiac causes were responsible for more than half of late deaths. This may reflect the burden of multiple comorbidities in our patients, as well as prevention of cardiac deaths resulting from recent advances in pharmacologic treatment of left ventricular dysfunction. Since coronary intervention has not been shown to prevent death in patients with stable symptoms, symptomatic improvement is an important outcome. In our patients, 85% reported that symptoms were improved compared to before their intervention, and 67% reported no recurrence of chest discomfort during the follow-up period. This confirms Di Sciascio’s finding that 80% of patients were symptom-free at follow-up. Study limitations. First, we excluded patients with an EF less than or equal to 40% who did not receive a stent. We did this to focus on the outcome of patients who underwent PCI with optimal technology, which at the time of this study included stents. DES were not available during the study period, and outcomes using DES may have been better. Ejection fractions were determined by visual estimation, not quantitatively, because in our experience, quantitative ventriculography routinely over-estimates EF. In our practice, visual estimation of EF in individual patients is constantly benchmarked against echocardiographic and nuclear imaging estimates of EF. To exclude the possibility that inclusion of higher-end EF patients was unduly influencing our results, we repeated analyses using only patients with an EF less than or equal to 35% and obtained essentially the same results as in the cohort including all patients with EF less than or equal to 40%. We did not survey patients on their use of medications at the time of follow-up. Finally, the results of this study may reflect the experience of a small group of experienced interventionists, and may not be generalizeable to all other angioplasty centers. In summary, current percutaneous coronary stenting techniques can be performed with high procedural success and low in-hospital complication rates in patients with an EF less than or equal to 40%. Long-term mortality remains significant, due to both cardiac and noncardiac causes of death. PCI in selected symptomatic patients with an EF less than or equal to 40% usually produces clinical improvement that is sustained at a mean of 2-year follow-up.

1. Lewin RF, Dorros G. Percutaneous transluminal coronary angioplasty in patients with severe left ventricular dysfunction. Cardiol Clin 1989;7;81–93. 2. Kohli RS, Di Sciascio G, Cowly M, Nath A. Coronary angioplasty in patients with severe left ventricular dysfunction. J Am Coll Cardiol 1990;16:807–811. 3. Stevens T, Kahn JK, McClallister BD, et al. Safety and efficacy of percutaneous coronary angioplasty in patients with left ventricular dysfunction. Am J Cardiol 1991;68:313–319. 4. Serota H, Deligonul U, Lee W-H, et al. Predictors of cardiac survival after percutaneous transluminal coronary angioplasty in patients with severe left ventricular dysfunction. Am J Cardiol 1991;67:367–372. 5. Eltchaninoff H, Franco I, Whitlow P. Late results of coronary angioplasty in patients with left ventricular ejection fractions