Issues of QCA validation

Influence of residual stenosis after percutaneous coronary intervention with stent implantation on development of restenosis and stent thrombosis

The aim of this study was to assess the effects of residual stenosis after single-stent implantation on the rate of stent thrombosis, as well as restenosis within a 6-month follow-up period. Coronary angiograms of 2,157 patients with 2,523 lesions treated with a single stent were analyzed by quantitative coronary angiography before, immediately after stent implantation, and at a planned 6-month follow-up. Lesions were classified into 4 subgroups according to the degree of residual stenosis after stent implantation: group 1, gross oversizing <-15%; group 2, slight oversizing -15% to <0%; group 3, mild residual 0% to <15%; group 4, moderate residual 15% to <30%. Stent thrombosis rates were not significantly different among the 4 subgroups (group 1: 0 of 60 [0%]; group 2: 2 of 388 [0.5%]; group 3: 8 of 1,370 [0.6%]; group 4: 8 of 705 [1.1%]; p = NS for all). An adequate dosage of ticlopidine (250 mg twice daily) and aspirin (100 mg/day) led to a lower rate of stent thrombosis (6 of 2,189 cases) than inadequate dosages or missing therapy (12 of 343 cases). In 1,882 stenoses with angiographic follow-up (77.7%), gross oversizing of stents lead to a significantly higher increase of percent stenosis (p <0.001) associated with a higher restenosis rate (group 1: 34.7% vs groups 2, 3, and 4: 32.5%, 28.2%, and 29.6%, respectively). A multiple regression analysis was performed. Optimal results with regard to stent thrombosis and restenosis were achieved with mild residual stenoses between 0% and 15% after stent implantation. Oversizing of stents is no longer necessary with an adequate dosage of ticlopidine and aspirin.

Comparison of two different methods of quantitative coronary angiography in patients with acute coronary syndromes

The minimal cost algorithm (MCA) commonly used for quantitative coronary arteriography has limitations in definition of complex lesion morphology. A gradient field transform (GFT) algorithm has been designed for the better analysis of complex lesions. We compared MCA with GFT in angiograms of 125 patients in the Myocardial Infarction with Novastan and t-PA (MINT) trial. Lesion border definition was rated as one (poor), two (good), or three (very good). While MCA- and GFT-derived reference diameters (RDs) were similar, GFT yielded smaller minimal lumen diameter (MLD) than MCA by 0.22 +/- 0.31 mm (P < 0.01), and the difference between GFT- and MCA-derived MLDs increased with decreasing MLD. Mean percent diameter stenosis (% DS) was 9.1% +/- 11.1% greater by GFT (P < 0.001). Lesion border definition in simple lesions was similar (not significantly different). However, in complex lesions GFT performed better (2.49 +/- 0.61 vs. 2.11 +/- 0.74; P < 0.05). Thus, GFT appears to improve analysis of complex lesions compared to MCA. GFTs role in angiographic trials and clinical practice deserves further study.

The role of acute wall recoil and late restenosis: results of the OCBAS trial (Optimal Coronary Balloon Angioplasty with Provisional Stenting versus Primary Stent)

Early deterioration of minimal luminal diameter immediately after PTCA, has been associated with an increase of late restenosis. Lesions with no early loss after PTCA have a low restenosis rate. Coronary stents reduce restenosis in lesions exhibiting early wall recoil. The purpose of the OCBAS study was to compare two strategies during coronary interventions; provision vs. elective stenting. 116 patients with good PTCA results were randomized to stent (n = 57) or to optimal PTCA (n = 59). After randomization in PTCA group, 13.5% of the patients crossed over to stent due to early loss (provisional stenting). Baseline demographic and angiographic characteristics were similar in both groups of patients. At 7.6 months, 96.6% of the entire population had a follow-up angiographic study; 98.2% in the stent and 94.9% in the PTCA group. Immediate and follow-up angiographic data showed that acute gain was significantly higher in the stent than in the PTCA group (1.95 vs. 1.5 mm; P < 0.03). However, late loss was significantly higher in the stent than the PTCA groups (0.63 +/- 0.59 vs. 0.26 +/- 0.44, respectively; P = 0.01). Hence, net gain with both techniques was similar (1.32 +/- 0.3 vs. 1.24 +/- 0.29 mm for the stent and PTCA groups respectively; P = NS). Angiographic restenosis rate at follow-up (19.2% in stent vs. 16.4% in PTCA; P = NS) and TVR (17.5 in stent vs. 13.5% in PTCA; P = NS) were also similar. Furthermore, event-free survival was 80.8% in the stent versus 83.1% in the PTCA group (P = NS). Overall costs (hospital and follow-up) were US$591,740 in the stent versus US$398,480 in the PTCA group (P < 0.02). The strategy of the PTCA with delay angiogram and provisional stent if early loss occurs, had similar restenosis rate and TVR than universal use of bare stents.

Are patients with renal failure good candidates for percutaneous coronary revascularization in the new device era?

BACKGROUND

Patients with end-stage renal disease undergoing conventional balloon angioplasty have reduced procedural success and increased complication rates. This study was designed to determine the immediate and long-term outcomes of patients with varying degrees of renal failure undergoing percutaneous coronary intervention in the current device era.

METHODS AND RESULTS

We compared the immediate and long-term outcomes of 362 renal failure patients (creatinine >1.5 mg/dL) with those of 2972 patients with normal renal function who underwent percutaneous coronary intervention between 1994 and 1997. Patients with renal failure were older and had more associated comorbidities. They had reduced procedural success (89.5% versus 92.9%, P:=0.007) and greater in-hospital combined major event (death, Q-wave myocardial infarction, emergent CABG; 10.8% versus 1.8%; P:<0.0001) rates. Renal failure was an independent predictor of major adverse cardiac events (MACEs) (OR, 3.41; 95% CI, 1.84 to 6.22; P:<0.00001). Logistic regression analysis identified shock, peripheral vascular disease, balloon angioplasty strategy, and unstable angina as independent predictors of in-hospital MACEs in the renal group. Compared with 362 age- and sex-matched patients selected from the control group, patients with renal failure had a lower survival rate (27.7% versus 6.1%, P:<0.0001) and a greater MACE rate (51% versus 33%, P:<0.001) at long-term follow-up. Cox regression analysis identified age and PTCA strategy as independent predictors of long-term MACEs in the renal group. Finally, within the renal failure population, the dialysis and nondialysis patients experienced remarkably similar immediate and long-term outcomes.

CONCLUSIONS

Although patients with renal failure can be treated with a high procedural success rate in the new device era, they have an increased rate of major events both in hospital and at long-term follow-up. Nevertheless, utilization of stenting and debulking techniques improves immediate and long-term outcomes.

Risk predictors in patients scheduled for percutaneous coronary revascularization

Traditionally, procedural risks associated with conventional balloon coronary angioplasty have been largely attributed to unfavorable lesion morphology. However, factors predicting adverse events in the current practice of percutaneous coronary revascularization are unclear. The present study was undertaken to determine factors predicting major adverse events (death or Q-wave myocardial infarction or emergency bypass surgery) in 3,335 consecutive patients undergoing percutaneous coronary revascularization in the current practice of percutaneous coronary revascularization. During the period of observation, the rate of lesions treated successfully increased from 91% to 95% (P < 0.0001), whereas the rate of major adverse events (MACE) decreased from 3.6% to 1.6% (odds ratio [OR], 0.70 per year). Using multiple stepwise logistic regression analysis, cardiogenic shock (OR, 8.59; confidence interval [CI], 4.27-17.27), renal disease (OR, 3.33; CI, 1.95-5.69), evolving myocardial infarction (OR, 2.80; CI, 1.47-5.31), congestive heart failure (OR, 2.18; CI, 1.23-3.86), total number of lesions treated (OR, 1.28; CI, 1.03-1.59), age (OR, 1.03; CI, 1.01-1.06), and history of prior coronary intervention (OR, 0.51; CI 0.26-0.99) were identified as independent predictors of MACE. In addition, vascular disease (OR, 2. 48; CI 1.37-4.50) and unstable angina pectoris (OR, 0.44; CI 0.25-0. 79) were related to adverse events when patients in cardiogenic shock were excluded from the model. With the exception of most unfavorable lesion morphology (AHA/ACC lesion type C; OR, 2.05; CI, 1.19-3.52), anatomic parameters added no further information. In the present era of device technology, success rates of percutaneous coronary revascularization procedures have increased and remain to be determined by lesion morphology. In contrast, the rate of MACE is declining and best predicted by easily identified patient characteristics.

Implications of small reference vessel diameter in patients undergoing percutaneous coronary revascularization

OBJECTIVES

The purpose of this study was to determine whether small reference diameter of the culprit coronary artery influences the outcome of an attempted percutaneous revascularization procedure in the current era of interventional cardiology.

BACKGROUND

Although the interventional strategy is largely determined by the size of the culprit coronary artery, earlier quantitative studies have not shown a worse acute outcome for small reference vessel diameter (< or =2.5 mm).

METHODS

A total of 2,306 patients undergoing percutaneous coronary revascularization was divided in groups with reference diameters < or =2.5 mm (n = 813) or >2.5 mm (n = 1,493). Success and in-hospital major adverse cardiac event (death, Q-wave myocardial infarction and emergency coronary artery bypass graft) rates between both groups were compared.

RESULTS

Patients with lesions in small vessels were older and presented more frequently with female gender, diabetes mellitus, heart failure, peripheral vascular, multivessel coronary disease and American Heart Association/American College of Cardiology (AHA/ACC) lesion type C (p < or = 0.01, each). Further, utilization of interventional devices differed markedly. In contrast to stents (18.5% vs. 41.9%) and directional atherectomy (3.7% vs. 13.5%), conventional balloon angioplasty (73% vs. 50%) and rotational atherectomy (16.1% vs. 8.3%) were used more often in smaller vessels (p < or = 0.0001, each). Success rate was lower in the small vessel group (92% vs. 95%; p = 0.006). Major adverse cardiac events occurred more frequently in small than large vessels (univariate 3.4% vs. 2.0%, p = 0.03; multivariate odds ratio 2.1, p = 0.02), particularly when proximal coronary segments were compared.

CONCLUSIONS

Lesions in vessels with small reference diameter represent a distinct group with respect to clinical and morphologic characteristics as well as device utilization. These lesions have lower chances of successful percutaneous intervention and carry relatively higher risks, specifically when located in proximal coronary segments.

Optimal coronary balloon angioplasty with provisional stenting versus primary stent (OCBAS): immediate and long-term follow-up results

OBJECTIVE

This study sought to compare two strategies of revascularization in patients obtaining a good immediate angiographic result after percutaneous transluminal coronary angioplasty (PTCA): elective stenting versus optimal PTCA. A good immediate angiographic result with provisional stenting was considered to occur only if early loss in minimal luminal diameter (MLD) was documented at 30 min post-PTCA angiography.

BACKGROUND

Coronary stenting reduces restenosis in lesions exhibiting early deterioration (>0.3 mm) in MLD within the first 24 hours (early loss) after successful PTCA. Lesions with no early loss after PTCA have a low restenosis rate.

METHODS

To compare angiographic restenosis and target vessel revascularization (TVR) of lesions treated with coronary stenting versus those treated with optimal PTCA, 116 patients were randomized to stent (n=57) or to optimal PTCA (n=59). After randomization in the PTCA group, 13.5% of the patients crossed over to stent due to early loss (provisional stenting).

RESULTS

Baseline demographic and angiographic characteristics were similar in both groups of patients. At 7.6 months, 96.6% of the entire population had a follow-up angiographic study: 98.2% in the stent and 94.9% in the PTCA group. Immediate and follow-up angiographic data showed that acute gain was significantly higher in the stent than in the PTCA group (1.95 vs. 1.5 mm; p < 0.03). However, late loss was significantly higher in the stent than the PTCA group (0.63+/-0.59 vs. 0.26+/-0.44, respectively; p=0.01). Hence, net gain with both techniques was similar (1.32< or =0.3 vs. 1.24+/-0.29 mm for the stent and the PTCA groups, respectively; p=NS). Angiographic restenosis rate at follow-up (19.2% in stent vs. 16.4% in PTCA; p=NS) and TVR (17.5% in stent vs. 13.5% in PTCA; p=NS) were similar. Furthermore, event-free survival was 80.8% in the stent versus 83.1% in the PTCA group (p=NS). Overall costs (hospital and follow-up) were US $591,740 in the stent versus US $398,480 in the PTCA group (p < 0.02).

CONCLUSIONS

The strategy of PTCA with delay angiogram and provisional stent if early loss occurs had similar restenosis rate and TVR, but lower cost than primary stenting after PTCA.

Coronary stenting in patients undergoing percutaneous transluminal coronary angioplasty during acute myocardial infarction

Although coronary stenting has been useful in the treatment of patients with suboptimal results, abrupt closure, and threatening occlusion after percutaneous transluminal coronary angioplasty (PTCA), its use in patients with acute myocardial infarction (AMI) is controversial because of the presence of intracoronary thrombus. In this study intracoronary stenting was used to treat suboptimal results and complications in 30 patients (35 lesions) undergoing PTCA during AMI. There were 28 men and 2 women, mean age 58 +/- 12 years. Thirteen patients (43%) had undergone rescue PTCA because of unsuccessful thrombolysis. Four patients had Killip's grade IV, 5 Killip's grade III, and 21 Killip's grade < or = 2 heart failure. Stents were placed in the 35 lesions because of suboptimal result (n = 19), early loss (n = 9), abrupt closure (n = 2), and coronary dissection with threatening occlusion (n = 5). All stents were deployed successfully. In-hospital complications included 1 in-hospital death (3.0%); no patient required emergency coronary artery bypass graft surgery. One patient (3.0%) developed abrupt closure and was successfully treated with PTCA and intracoronary thrombolysis. Vascular complications requiring blood transfusion developed in 3 of 30 patients (10%). At 11.8 months (range 4 to 24) follow-up, there were no deaths or myocardial infarction. One patient underwent coronary artery bypass grafting. The remaining patients were free of angina at follow-up. Thus, intracoronary stents can be used successfully to treat both suboptimal results and complications occurring in patients undergoing PTCA during AMI.