[Coronary surgery].

BACKGROUND: Recent changes in health care financing have raised the specter of operation-specific, volume credentialing for cardiac surgeons. To meet this challenge, the leadership of The Society of Thoracic Surgeons formed an Ad Hoc Committee to study the question of the relationship of case volume to outcome. One product of the committee's work in this analysis of data from The Society of Thoracic Surgery National Cardiac Database. METHODS: We examined data for all types of coronary artery bypass graft-only operations (n = 124,793) from more than 1,200 surgeons working in more than 600 hospitals for the years 1991 through 1993. All in-hospital and 30-day out-of-hospital mortality, both observed and expected as predicted by The Society of Thoracic Surgeons risk stratification method, was plotted against annualized group practice volume. Both patient-based and practice-based sampling techniques were used. RESULTS: The data show that observed mortality ranged from 2.0% to 3.6% for practices of more than 100 cases through practices with more than 900 cases per year. Those practices with less than 100 cases (n = 18) had a mean mortality of 5%. Expected mortalities ranged from 2.4% to 3.9% and did not vary as a function of volume. No practice volume category had an observed/expected ratio of less than 0.8 and none had a ratio greater than 1.2, if annual volume was more than 100. Practices of less than 100 cases/year had an observed/expected ratio of 1.6% to 1.7%. There was great variation in observed and expected mortalities in the lower volume categories and less variation when volume was greater (more than 600 cases/year). CONCLUSIONS: Although the data are practice-group-specific only, there was no clinically relevant correlation of volume to outcome except at extremely low annual volume (less than 100 cases per year). Variability of outcome was significant in lower volume practices (less than 600 cases/year) and varied little at more than 600 cases per year. There were no differences in expected mortality regardless of the size of the practice.

Coronary Artery Bypass↗

PubMed1996

Use of verapamil and nitroglycerin solution in preparation of radial artery for coronary grafting.

BACKGROUND: The radial artery (RA) has been used as an alternative arterial graft for coronary artery bypass grafting. This artery has been reported to be spastic; therefore, use of spasmolytic drugs (vasodilators) during the preparation of the RA is recommended. The combination of calcium antagonists and nitroglycerin (verapamil plus nitroglycerin, VG solution) has been suggested to be effective in other bypass grafts. This study was designed to investigate (1) the effect of the VG solution during preparation of the RA for coronary artery bypass grafting and (2) whether the effect would last for a prolonged period after topical use. METHODS: Ring segments of the RA taken from coronary artery bypass grafting patients were studied in organ chambers at a physiologic pressure. The relaxation effect of VG (30 mumol/L verapamil and 30 mumol/L nitroglycerin, n = 5) or papaverine (30 mumol/L, n = 5) was recorded in K+ (25 mmol/L potassium chloride)-precontracted RA segments. Other segments taken from the RA were treated (n = 5) or not treated (n = 20, as the control) with the VG solution for 45 minutes before used for coronary artery bypass grafting. Both the VG-treated and nontreated segments were immersed in oxygenated Krebs solution and stored in a refrigerator at 4 degrees C for 24 hours. The contraction force to 100 mmol/L K+ was compared between the two groups. RESULTS: The VG solution induced more rapid relaxation than papaverine (p < 0.05 from the first to the ninth minute). After 10 minutes, both solutions induced full relaxation. The contraction to K+ (100 mmol/L) in rings treated with VG solution for 45 minutes during operation was almost abolished 24 hours later (0.86 +/- 0.1 g). In contrast, the control segments (n = 20) taken from nontreated RA contracted with K+ to high force (5.0 +/- 0.6 g; p < 0.001). CONCLUSIONS: The present study suggests that the combination of verapamil and nitroglycerin may provide a rapid onset, a complete relaxation, and a long-lasting vasorelaxant effect when used to prepare the RA for grafting. This study adds a new method to prevent RA spasm during coronary artery bypass grafting.

Coronary Artery Bypass↗