Canadian Coronary Atherectomy Trial - CCAT

Description:

Directional atherectomy vs. PTCA for angiographic estenosis in LAD lesions.

Hypothesis:

To assess the clinical and angiographic outcomes following atherectomy for de novo lesions in the proximal left anterior descending artery (LAD).

Study Design

Study Design:

Patients Screened: 4,024
Patients Enrolled: 274
Mean Follow Up: 18 months
Mean Patient Age: 56
Female: 16

Patient Populations:

Angina or objective evidence of myocardial ischemia
Stenosis of ≥ 60% in the proximal third of the left anterior descending coronary artery
Lesion suitable for either atherectomy or angioplasty.

Exclusions:

Restenosed lesions
Lesion length of > 10mm
Ostial or bifurcation lesions
Total occlusion
Vessel size of < 3mm
Heavy calcification
Severe tortuosity
Left main coronary stenosis exceeding 25 percent
Acute myocardial infarction within 1 week
Severe left ventricular dysfunction or cardiogenic shock
Medical conditions likely to preclude follow-up angiography

Primary Endpoints:

Angiographic restenosis

Concomitant Medications:

Aspirin, calcium channel blockade, nitrates.
Beta blockers were to be tapered and discontinued following the procedure unless they were required for hypertension or other specific indications.

Principal Findings:

Of 4024 patients screened, 1718 had lesions of the left anterior descending coronary artery; of these patients, 81 percent had angiographic and 12 percent clinical reasons for exclusion.

Of the 274 patients selected for the study, 138 were randomly assigned to undergo atherectomy and 136 to undergo angioplasty. Fifty-eight percent of all atherectomy procedures performed at the study centers were included in the trial.

Angiographic success was achieved in 135 of 138 patients undergoing atherectomy (98 percent) and 124 of 136 patients undergoing angioplasty (91 percent) (P = 0.017).

There were no in-hospital deaths and only one Q-wave myocardial infarction. The incidence of other major complications, including in-hospital coronary bypass surgery and non-Q-wave myocardial infarction, was similar in the two groups (composite outcome: 5 percent for the atherectomy group and 6 percent for the angioplasty group; P = 0.98).

Angiography was performed a median of 5.9 months after the procedure in 257 patients. The rate of restenosis was 46 percent in the atherectomy group (95 percent confidence interval, 37 to 54 percent) and 43 percent in the angioplasty group (95 percent confidence interval, 34 to 52 percent) (P = 0.71).

Six-month clinical data were available for all 265 patients eligible for follow-up. There were no significant differences between the two groups with regard to clinical events. One sudden death occurred in a patient who had undergone atherectomy, and there were two myocardial infarctions, both in patients who had undergone angioplasty. Revascularization was repeated in 39 patients in the atherectomy group and 36 patients in the angioplasty group. Seventy-one percent of the patients in each group had no late adverse events.

To determine whether late differences emerged between the groups, clinical follow-up was obtained at a median of 18 (range 10 to 31) months after randomization. There were no differences in adverse events between the two groups during follow-up. In patients randomized to atherectomy compared with balloon angioplasty, the combined end-point of death or nonfatal myocardial infarction occurred in nine (6.6%) versus 11 (8.1%) patients and any adverse cardiac event in 50 (36.5%) versus 53 (39.3%).

Interpretation:

In addition to compressing and reshaping atheroma, atherectomy excises tissue and debulks plaques; it was anticipated that this mechanism would result in a lower rate of restenosis than that occurring after angioplasty. These expectations were not fulfilled in this trial. Although the procedural success rate was somewhat higher and the postprocedure lumen larger in patients treated with atherectomy, lumen dimensions, restenosis rates and clinical outcomes were similar in the two groups at six months. Clinical outcomes for the two groups were similar at up to 18 months after the procedure.

References:

1. N Engl J Med 1993;329:228-33. Final results
2. Canadian Journal of Cardiology 1997;13:825-30. 1-year follow-up

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery

Keywords: Myocardial Infarction, Plaque, Atherosclerotic, Atherectomy, Coronary, Death, Sudden, Coronary Disease, Constriction, Pathologic, Coronary Vessels, Angioplasty, Balloon, Coronary


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