Triple Vessel Stenting for Triple Vessel Coronary Disease

Overall cumulative survival (diamond) and survival free of major adverse events (square) of 115 patients.
Author(s): 

Beatriz Villegas, MD, Marie-Claude Morice, MD, Salvador Hernandez, MD,
Rémi Choussat, MD, Pierre Dumas, MD, Thierry Lefèvre, MD, Yves Louvard, MD, Christophe Loubeyre, MD, Jean Fajadet, MD, Jean Marco, MD

When percutaneous coronary intervention (PCI) was introduced, it was limited to patients suffering from refractory angina pectoris due to isolated lesions of a single major epicardial coronary artery.1 Over the last 2 decades, however, the treatment of multivessel coronary disease has expanded from surgical bypass to include PCI with and without implantation of stents.2 Coronary artery bypass graft surgery (CABG) has been shown to prolong survival of patients with left main or triple vessel coronary disease, significant ischemia, or left ventricular dysfunction.3 On the other hand, controlled and uncontrolled studies have confirmed the feasibility of multivessel coronary stenting and, in selected patients, it has been associated with a comparable short-term survival to CABG.2,4–10 However, studies published thus far have not focused on patients with triple vessel coronary disease, and have generally included a majority of patients with single or double vessel disease.
Since the publication of the most recent studies, percutaneous revascularization techniques have evolved significantly, and stenting, which is now attempted nearly systematically, has increased the safety of the procedures and reduced the risk of restenosis. Thus, in a carefully selected patient population with multivessel coronary disease, stenting may be a desirable alternative to CABG. However, in actual clinical practice, most patients with triple vessel coronary disease are regularly managed surgically on the basis of recommended guidelines, presence of one or more occluded vessels judged unsuitable for PCI, and high expected restenosis rate of a triple vessel procedure.
This study was performed to measure the percentage of candidates for multiple stenting of triple vessel coronary artery disease among a large population of consecutive patients undergoing elective PCI, and to examine their short- and intermediate-term outcomes.

METHODS

Study population. The overall study population consisted of 6,810 consecutive patients who underwent PCI and were prospectively entered into a registry kept at 2 medical centers, by 7 experienced interventional cardiologists, between January 1996 and January 1999. During that period, angioplasty with stenting was systematically offered to the patients as an alternative to surgery whenever complete revascularization with a finite number of stents was judged feasible. This report focuses on the clinical characteristics and outcomes of a subgroup of 115 patients who underwent successful implantation of stents after PCI performed for miscellaneous immediate indications, in the context of multiple vessel disease, usually in a single procedure.
Patients were considered for this therapeutic strategy if they had type A, B1 or B2 lesions of all 3 major epicardial coronary arteries, judged manageable with PCI and stenting. They were excluded if they had type C coronary lesions, contraindications to antiplatelet therapy or anticoagulation, left main coronary artery disease, coronary luminal diameter < 2.5 mm, diffuse atherosclerotic disease or significant associated valvular disease. In addition, patients who had > 1 complex lesion or the need for > 80 mm stent length were not recommended to have percutaneous PCI and were advised to undergo CABG.
PCI was performed by standard techniques via femoral or radial approaches, as described previously.11,12 In each procedure, attempts were made to achieve complete revascularization by dilating all coronary stenoses > 60%, in a single session whenever possible. A standard 12-lead electrocardiogram (ECG) was recorded before and immediately after each procedure, as well as 24 hours later, in search of signs of myocardial ischemia, new abnormal Q-waves, or both. CK enzymes were systematically measured on the day after each procedure and CK-MB enzyme fraction was also measured if total CK was greater than twice the upper limit of normal values in our laboratory.

Drug treatment protocol. Intravenous heparin was administered during each procedure as an initial 7,500–10,000 U bolus, followed by additional intermittent doses to maintain an activated clotting time >= 300 seconds. All patients who were not pretreated with oral aspirin received 250 mg of intravenous aspirin before each procedure followed by aspirin 100 mg daily indefinitely thereafter. Oral ticlopidine 250–500 mg daily was begun immediately after the procedure and continued for 4 weeks. Treatment with abciximab was administered to < 2% of patients.

Stent implantation and angiographic analysis. All lesions were predilated and stents were implanted with a pressure dilatation of 10–20 atmospheres, as required to achieve <= 10% residual stenosis. Angiographic imaging was performed in 2 orthogonal views after intracoronary injection of nitrates. Each lesion was measured before and after stenting on unoptically magnified cineangiographic frames showing the lesion in its highest grade, using the guiding catheter as reference. Measurements of the diameter of the guiding catheter, the minimal vessel lumen diameter, and percent stenosis before and after stenting were performed by automatic contour edge detection (General Electric Medical Systems, Milwaukee, Wisconsin). Intravascular ultrasound imaging was not used.

Patient follow-up. Patients were prospectively followed by telephone interviews and outpatient department visits scheduled at 3, 6, 12, 24 and 36 months after each procedure. All data collected were stored in a regularly updated computer database.

Definitions. Multivessel disease was defined as >= 60% stenosis of 3 major epicardial coronary arteries or branches. Dilatations of tandem lesions within the same vessel were treated as dilatations of a single vessel. Procedural success was defined as success of all attempts to dilate lesions in the 3 coronary arteries, with < 20% residual stenosis, with the absence of major in-hospital complications including myocardial infarction, CABG or death. Myocardial infarction was defined as a new increase in Q-wave pattern >= 2 grades according to the Minnesota code,13 or new left bundle branch on 12-lead ECG, and/or a rise in total CK enzyme above twice the upper limit of normal values and an abnormal MB isoenzyme fraction. Diabetes was defined as a history of diabetes and use of insulin or oral hypoglycemic agents on entry into the study.

Statistical analysis. Statistical analyses were performed with SAS 6.08 software. Data were summarized using means and standard deviation (SD) for continuous variables and frequency for categorical variables. Univariate analysis was performed by student's t-test or Chi-square test, as appropriate. Survival and event-free survival, i.e., freedom from death, myocardial infarction or further revascularization procedures, were analyzed by the Kaplan-Meier method. All values are expressed as means ± SD. All p-values were 2-tailed and considered significant if less than or equal to 0.05.

RESULTS

The baseline characteristics and clinical presentation of the 115 patients analyzed in this report are presented in Table 1. Stable or unstable angina pectoris was the indication for the procedure in nearly 3 out of 4 patients. A total of 483 lesions were stented, representing a mean of 4.2 ± 1.4 stents per patient. The types of stents implanted and rates of their use are shown in Table 2. Table 3 lists the vessels in which stents were implanted in order of frequency. The left anterior descending and the right coronary arteries were the site of implantation in > 80% of instances, and the left marginal and circumflex arteries each received stents approximately 50% of the time. The mean luminal diameter of the treated vessels was 2.9 ± 0.3 mm and the mean total length of stents implanted was 66.9 ± 24.9 mm.

In-hospital outcomes. Stenting of all vessels was accomplished in a single session in 89 patients (78%), and in interventions staged within 1 week in 26 patients (22%). Angiographically successful revascularization was achieved in 113 patients (98.7%). Major in-hospital adverse events included death in 2 patients (1.7%), Q-wave myocardial infarction in 1 patient (0.8%), non-Q wave myocardial infarction in 4 patients (3.6%), and emergent and non-emergent CABG in 1 patient (0.8%) each. The mean duration of hospitalization of surviving patients was 2.7 ± 2.2 days.

Long-term follow-up. Over an average follow-up period of 16 ± 14 months (range, 1–36 months) on all but a single patient (99.1%), four patients (3.4%) died, five patients (4.3%) underwent CABG, and 23 patients (20%) underwent further PCI (Table 4). The overall cumulative survival and the survival-free of major adverse events up to 36 months are presented in Figure 1.
Univariate analysis of all clinical, angiographic and procedural variables tested showed that younger age and stented coronary segments > 80 mm were the only predictors of need for additional target vessel revascularization (Table 5).

DISCUSSION


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