The right ventricular annular velocity reduction caused by coronary artery bypass graft surgery occurs at the moment of pericardial incision.

BACKGROUND: Right ventricular (RV) long-axis function is known to be depressed after cardiac surgery, but the mechanism is not known. We hypothesized that intraoperative transesophageal echocardiography could pinpoint the time at which this happens to help narrow the range of plausible mechanisms. METHOD: Transthoracic echocardiography was conducted in 33 patients before and after elective coronary artery bypass graft. In an intensively monitored cohort of 9 patients, we also monitored RV function intraoperatively using serial pulsed wave tissue Doppler (PW TD) transesophageal echocardiography. RESULTS: There was no significant difference in myocardial velocities from the onset of the operation up to the beginning of pericardial incision, change in RV PW TD S' velocities 3% +/- 2% (P = not significant). Within the first 3 minutes of opening the pericardium, RV PW TD S' velocities had reduced by 43% +/- 17% (P < .001). At 5 minutes postpericardial incision, 2 minutes later, the velocities had more than halved, by 54% +/- 11% (P < .0001). Velocities thereafter remained depressed throughout the operation, with final intraoperative S' reduction being 61% +/- 11% (P < .0001). One month after surgery, in the full 33-patient cohort, transthoracic echocardiogram data showed a 55% +/- 12% (P < .0001) reduction in RV S' velocities compared with preoperative values. CONCLUSIONS: Minute-by-minute monitoring during cardiac surgery reveals that, virtually, all the losses in RV systolic velocity occurs within the first 3 minutes after pericardial incision. Right ventricular long-axis reduction during coronary bypass surgery results not from cardiopulmonary bypass but rather from pericardial incision.

Does previous percutaneous coronary stenting compromise the long-term efficacy of subsequent coronary artery bypass surgery? A microsimulation study.

BACKGROUND: This study aims to compare long-term survival and health-related quality of life in patients undergoing coronary artery bypass surgery with and without previous coronary stenting. METHODS: Markov microsimulation was used to model long-term survival and quality of life after surgical revascularization using data from referenced sources. Probabilistic sensitivity analysis was used to investigate the effect of uncertainty associated with the model parameters on the microsimulation results. RESULTS: Percutaneous coronary stenting was found to significantly decrease the effectiveness of coronary surgery. The model suggests that after a single stenting procedure ten-year survival was reduced by 3.3% (SD 0.7%), from 79.9% (SD 1.3%) to 76.6% (SD 1.4%). Similarly, after multiple stenting procedures ten-year survival was reduced by 3.5% (SD 0.7%) to 76.4% (SD 1.4%). Over a ten-year period a single stenting procedure reduced the quality adjusted life year (QALY) payoff by 0.25 QALY (SD 0.11 QALY) and multiple stenting procedures reduced the QALY payoff by 0.27 QALY (SD 0.08 QALY). CONCLUSIONS: This study suggests that patients who undergo surgical bypass after stenting have worse long-term outcomes than patients who undergo surgical revascularization without previous percutaneous intervention. The pathophysiological mechanisms for this are not fully understood and must be further investigated. The findings of this study suggest that the timing of surgical bypass in relation to percutaneous intervention is important. This may have significant implications for clinical practice, suggesting that greater emphasis should be placed on selecting the optimum initial revascularization strategy.