Safety of beating heart anastomosis during video-assisted coronary surgery attested by cardiac troponin I

[Cardiac biomarkers for diagnosis of myocardial infarction]

Diagnosis of postoperative myocardial infarction is often difficult, based on tools with a low sensitivity (clinical symptoms, EKG), or with a low specifity (old biomarkers, echocardiographic abnormalities) or inadequate for clinical practice (scintigraphy). Since 1995, clinicians may use more cardiospecific markers (troponin) allowing to modify strategy for postoperative myocardial infarction diagnosis. The aim of this review is to resume such an attitude.

Off-pump total arterial myocardial revascularization according to the right Y-graft configuration

OBJECTIVES

The aims of this study were as follows: 1) to evaluate the early outcome of the off-pump total arterial myocardial revascularization according to the right y-graft (lambda-graft) configuration and 2) to compare baseline flow and maximum flow between patients undergoing on-pump and off-pump right y-graft (RYG) construction.

METHODS

Between December 1998 and January 2001, 47 patients (Group I) and 20 patients (Group II) with three vessel disease underwent on-pump and off-pump coronary artery bypass graft (CABG) respectively according to the RYG configuration. The mean age was 55.5 +/- 4.7 years and 55 +/- 6.4 years in Groups I and II, respectively. The RYG was constructed employing both internal mammary arteries (IMAs) only, in 21 and 8 patients in Groups I and II, respectively, presenting proximal-middle third stenosis of the left anterior descending artery (LAD) and right coronary artery (RCA). The modified RYG configuration employing both IMAs and radial artery (RA) was performed in 26 and 12 patients in Groups I and II, respectively, presenting middle-distal third stenosis of the LAD and distal stenosis of the RCA or posterior descending artery stenosis. Postoperatively all patients underwent transthoracic echo color-Doppler (TTECD) contrast enhanced (by Levovist) before and after adenosine provocative testat one week and three months after operation.

RESULTS

There were no hospital deaths. The mean mechanical ventilation was significantly different in Group I versus Group II patients, 18 +/- 4.4 hours versus 13 +/- 5.7 hours, respectively (p = 0.041). The mean intensive care unit stay was 1.5 +/- 0.6 days in Group I and 1 +/- 0.4 days in Group II (p = 0.033). There were no differences between Groups I and II regarding the IMA diameter, mean velocity, and mean flow. At follow-up time, 6 +/- 2.4 months after the surgical procedure, all patients were alive and free of angina. The coronary flow reserve (CFR) at LIMA main stem was significantly higher at three months when compared to the values at one week after the surgical procedure within the same group, (LIMA)CFR (three months) = 2.37 +/- 0.6 versus (LIMA)CFR (one week) = 2.07 +/- 0.4 (p = 0.005) in Group I and (LIMA)CFR (three months) = 2.4 +/- 0.4 versus (LIMA)CFR (one week) = 2.06 +/- 0.3 (p = 0.004) in Group II. Similarly, the CFR at RIMA main stem were significantly higher at three months when compared to the values at one week after the surgical procedure: (RIMA)CFR (three months) = 2.47 +/- 0.7 versus (RIMA)CFR (one week) = 2.1 +/- 0.5 (p = 0.004) in Group I and (RIMA)CFR (three months) = 2.48 +/- 0.5 versus (RIMA)CFR (one week) = 2.08 +/- 0.4 (p = 0.008) in Group II.

CONCLUSION

The flow dynamic data, almost identical between patients undergoing off-pump and on-pump total arterial myocardial revascularization (TAMR) according to the RYG configuration, demonstrate that this technique can be applied with excellent results without the employment of cardiopulmonary bypass in selected coronary artery disease patients.

Serum cardiac troponin I after conventional and minimal invasive coronary artery bypass surgery

We evaluated myocardial release of cardiac troponin I (cTnI) in patients treated with conventional coronary artery bypass grafting (CABG), which employs extracorporeal circulation, and different kinds of minimal invasive coronary artery bypass grafting (MICABG), a surgical technique where the operation is performed without extra-corporeal circulation. Furthermore, we evaluated the usefulness of serum cTnI measurement to detect perioperative myocardial infarction (PMI) after coronary artery bypass surgery. Thirty-one patients were included: sixteen underwent CABG, fifteen underwent different MICABG and five patients had PMI. Blood specimens for cTnI measurements were collected up to 72 hours after opening the graft. Aortic cross-clamping time was a minor determinant of myocardial damage; on the other side, the trauma during surgery correlated with the number of involved arteries and with the manoeuvre employed to obtain heart dislocation, and appeared a more important determinant of myocardial damage. In patients with PMI, the cumulative release of cTnI was higher than in patients free from PMI; however, only after 24-72 hours we observed significant differences in serum cTnI values, because the increased perioperative values of cTnI complicated the interpretation of the myocardial status and a single cut-off could not be used to exclude PMI.