Nadim M. Zacca

Treatment of symptomatic peripheral atherosclerotic disease with a rotational atherectomy device

Narrowings 70 to 90% in diameter in 3 iliac, 4 superficial femoral and 2 popliteal arteries were crossed and atherectomized successfully in 6 patients using the Squibb Rotablator under angiographic guidance during surgical bypass procedures on these arteries. The Rotablator consists of a 1.25 to 4.5 mm diameter oblong burr with tiny diamond blades mounted on a flexible shaft, which tracks over a spring-tip guidewire and rotates at speeds greater than 120,000 rpm. All stenoses were reduced to less than or equal to 50% of the normal luminal diameter. No significant complications occurred. Of the 6 patients having the atherectomy procedure, 5 were reevaluated by duplex Doppler measurements 1.5 to 5.5 (mean 3.5) months after atherectomy and found to be patient with only mild residual flow disturbance. Repeat follow-up by angiography after a mean of 5.2 months, however, showed only 3 (37%) of the atherectomized segments in 3 patients to still be patent. All were symptomatically improved. Of the effluent particles analyzed, 90% were less than 8 microns in size, while only 5% reached 250 microns. With improvements in technique, the largest particles were 150 to 180 microns, constituting only 1.4% of effluent debris. Samples of the effluent from 2 patients were injected in vivo into the left coronary system of 2 pigs. There were no acute hemodynamic or electrocardiographic complications or pathologic evidence of muscle necrosis or vascular thrombosis 18 to 48 hours later. These preliminary results with respect to feasibility and safety of the Rotablator are promising.

Effects of digoxin on left ventricular function in coronary artery disease patients

To assess whether digitalis modifies or prevents the deterioration of the left ventricular ejection fraction and wall motion during acute ischemia, we performed gated blood pool radionuclide ventriculograms in 15 patients with angiographically documented coronary artery disease. All patients were studied in the resting state and during maximal supine bicycle exercise, both before and 1 hour after 1 mg intravenous digoxin. There was no significant difference, pre-digoxin vs post-digoxin, in exercise tolerance (415 +/- 84 vs 418 +/- 107 seconds), number of segments with abnormal resting wall motion (12 vs 11) or exercise wall motion (21 vs 19). Ten patients developed angina during the same exercise load, irrespective of digoxin administration. Twelve patients had subnormal left ventricular ejection fraction during exercise pre-digoxin, vs 13 patients post-digoxin (P = ns). In the resting state, the left ventricular ejection fraction was higher after digoxin (53 +/- 14% pre vs 58 +/- 14% post, P less than 0.05). During exercise, however, the left ventricular ejection fraction was not significantly improved after digoxin (50 +/- 16% pre vs 53 +/- 17% post, P = ns). These data indicate that although acute administration of digoxin improves the resting left ventricular function, it does not improve exercise tolerance to angina. Furthermore, intravenous digoxin does not appear to prevent the deterioration of left ventricular wall motion and ejection fraction during exercise induced ischemia.