[Cardiac troponin I in perioperative myocardial infarction after coronary artery bypass surgery]

Graft preservation confers myocardial protection during coronary artery bypass grafting

Background

During on-pump coronary artery bypass grafting (ONCAB), graft flushing for distal anastomoses testing also perfuses the downstream myocardium. This single-center retrospective study evaluated the impact of specific preservation solutions on myocardial protection during ONCAB.

Materials and methods

Between July 2019 and March 2020 either DuraGraft (DG) or 0.9% Saline/Biseko (SB) was applied to 272 ONCAB. Overall, 166 patients were propensity-matched into two groups. Cardiac enzymes [high-sensitive Troponin I (hs-TnI) and creatine kinase (CK)] were evaluated 7 days post-surgery.

Results

Post-surgery, hs-TnI values were significantly lower from 3 to 6 h (h) up to 4 days in the DG group: 3–6 h: 4,034 ng/L [IQR 1,853–8,654] vs. 5,532 ng/L [IQR 3,633—8,862], p = 0.05; 12–24 h: 2,420 ng/L [IQR 1,408–5,782] vs. 4,166 [IQR 2,052–8,624], p < 0.01; 2 days: 1,095 ng/L [IQR 479–2,311] vs. 1,564 ng/L [IQR 659–5,057], p = 0.02 and at 4 days: 488 ng/L [IQR 232–1,061] vs. 745 ng/L [IQR 319–1,820], p = 0.03. The maximum value: 4,151 ng/L [IQR 2,056–8,621] vs. 6,349 ng/L [IQR 4,061–12,664], p < 0.01 and the median area under the curve (AUC): 6,146 ng/L/24 h [IQR 3,121–13,248] vs. 10,735 ng/L/24 h [IQR 4,859–21,484], p = 0.02 were lower in the DG group. CK values were not significantly different between groups: maximum value 690 [IQR 417–947] vs. 631 [464–979], p = 0.61 and AUC 1,986 [1,226–2,899] vs. 2,081 [1,311–3,063], p = 0.37.

Conclusion

Repeated graft flushing with DG resulted in lower Troponin values post-surgery suggesting enhanced myocardial protection compared to SB. Additional studies are warranted to further assess the myocardial protection properties of DG.

Improvement in cardioplegic perfusion technique in single aortic clamping - initial results

INTRODUCTION

The most common method used for myocardial protection is administering cardioplegic solution in the coronary circulation. Nevertheless, protection may be achieved by intermittent perfusion of the coronary system with patient's own blood. The intermittent perfusion may be performed by multiple sequences of clamping and opening of the aortic clamp or due single clamping and accessory cannulation of the aortic root as in the improved technique proposed in this study, reperfusion without the need for multiple clamping of the aorta.

OBJECTIVE

To evaluate the clinical outcome and the occurrence of neurological events in in-hospital patients submitted to myocardial revascularization surgery with the "improved technique" of intermittent perfusion of the aortic root with single clamping.

METHODS

This is a prospective, cross-sectional, observational study that describes a myocardial management technique that consists of intermittent perfusion of the aortic root with single clamping in which 50 patients (mean age 58.5 ± 7.19 years old) have been submitted to the myocardial revasculrization surgery under the proposed technique. Clinical and laboratory variables, pre- and post-surgery, have been assessed.

RESULTS

The mean peak level of post-surgery CKMB was 51.64 ± 27.10 U/L in the second post-surgery and of troponin I was 3.35 ± 4.39 ng/ml in the fourth post-surgery, within normal limits. No deaths have occurred and one patient presented mild neurological disorder. Hemodynamic monitoring has not indicated any changes.

CONCLUSION

The myocardial revascularization surgery by perfusion with the improved technique with intermittent aortic root with single clamping proved to be safe, enabling satisfactory clinical results.

[Coronary endarterectomy and bypass grafting without cardiopulmonary bypass]

We prospectively analyzed patients who underwent simultaneous off-pump coronary artery bypass grafting and endarterectomy between March 1, 1997 and February 28, 2002. The incidence of perioperative myocardial infarction, need for inotropic support, morbidity, long-time functional class, and mortality were evaluated. Nine endarterectomies were performed in eight patients, more frequently in the right coronary artery. Dopamine was used in four patients. One perioperative myocardial infarction (12.5%) occurred. No deaths occurred and all patients are now functional class I. Tests for ischemia have been negative in all patients.Coronary endarterectomy is an alternative procedure that has little morbidity and enables complete myocardial revascularization without cardiopulmonary bypass.