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Between January 1979 and October 1991, percutaneous transluminal angioplasty of stenosed or occluded coronary bypass grafts was attempted 180 times in 146 patients (180 lesions in 157 bypass grafts); 6/157 grafts were internal mammary grafts. The procedure was successful in 129/157 grafts (82%) and in 151/180 lesions (84%). Failures occurred almost exclusively in recanalization attempts. Cardiac complications occurred in 4/146 patients (2.7%). Three patients developed an acute myocardial infarction, another patient died after acute occlusion of a native vessel dilated during the same procedure. In successful attempts the severity of stenosis was reduced from 87 +/- 10% to 33 +/- 15%. 113/129 successfully dilated grafts had at least one (mean 2.7) control angiogram. 54/113 (48%) showed recurrence after a mean follow up of 6 months. An additional 15 grafts showed late restenosis in a second control angiogram (mean follow-up 23 months). The total restenosis rate was 61%. Restenoses were dilated again one to six times (mean 1.9) with comparable success and recurrence rate. Two patients died during the sixth angioplasty. Finally, 32/129 (25%) grafts were occluded or presumably occluded, and 97/129 (75%) were angiographically confirmed open without restenosis. Thus, angioplasty of bypass grafts is an alternative to a repeat revascularization surgery. The acute results are comparable to the results of angioplasty in native coronary arteries. The restenosis rate is high. One has to be aware of late restenosis. Restenosis can be dilated repeatedly with a comparable success rate and with no significant increase in restenosis rate.

The unprotected left main stenosis still represents one of the contraindications of PTCA; recently developed concepts using percutaneous bypass techniques have not changed this fact so far. However, following bypass grafting the procedure can be done with low risk and may improve prognosis in case of later bypass occlusion. This study should clarify whether a higher rate of bypass occlusion is caused by postsurgical left main PTCA. From October 1981 to January 1991 a left main stenosis was dilated in 41 patients, 2 weeks to 12 years (mean 3.5 years) after bypass grafting. To date, 17/65 venous bypass grafts were already occluded, and 72.4% of the patients suffered from typical angina. In 34/41 patients (82.9%) PTCA was successful, severe complications (death, emergency surgery or myocardial infarction) did not occur and clinical improvement was achieved in 80% of symptomatic patients. Four months later, 26/34 patients (76.5%) had angiographic follow-up. Fifteen restenoses were found and a second PTCA was performed in 9/15. None of the venous bypass grafts, open at the time of the first PTCA, was occluded at follow-up. In one case PTCA of the left main stenosis turned out to be life-saving 7 years later because an occlusion of RCA- and LCX-bypasses occurred and the LAD graft showed a subtotal thrombosis. It is concluded that PTCA of left main stenosis after bypass grafting is a safe procedure and does not lead to a higher rate of venous bypass occlusions. A prognostic indication seems to be justified.

We report about the 6-month follow-up of 28 consecutive patients treated with a new tantalum stent (Wiktor¿ stent, Medtronic, Inc.). Indication for stenting was the prevention of restenosis in eight patients (restenosis group), and threatening or acute closure after PTCA in 20 patients (acute closure group). Twenty-eight of 30 stents were successfully positioned in 27 of 28 patients (96%), whereas implantation failed twice in one patient. Immediate stent occlusion developed in two patients in the acute closure group (7.4%) Subacute stent occlusion was observed in three patients (11%), one in the restenosis group, two in the acute closure group, between 3 and 5 days after implantation. Coronary bypass surgery had to be performed in four patients (15%): one patient after failed stent placement, two after acute, and one after subacute stent thrombosis. Major bleeding complications related to the anticoagulative drug regimen occurred in nine patients (33%). Three patients (11%) died for reasons most probably not related to stent implantation. A 6-month angiographic follow-up revealed restenosis in two of 19 patients (11%), one patient in each group. Sixteen of the 27 stented patients (59%) reached 6-month follow-up without death, acute or subacute stent thrombosis, or restenosis. It is concluded that the Wiktor stent can be placed with a high rate of success. It may also reduce the risk of restenosis. The stent also offers the possibility to circumvent emergency bypass surgery in case of PTCA related vessel occlusion. Acute and subacute stent occlusion still remains an unsolved topic.