Acute graft failure caused by an intracoronary shunt in minimally invasive direct coronary artery bypass grafting

Coronary artery spasm following off-pump coronary artery bypass surgery

Coronary artery spasm after coronary artery bypass surgery may result in life-threatening arrhythmias, circulatory collapse, or death. We report two cases of coronary artery spasm after coronary artery bypass surgery, one of which developed ventricular fibrillation requiring extracorporeal membrane oxygenation support. Both patients were discharged in good condition and are currently followed as outpatients. Unexpected sudden hemodynamic compromise could be due to coronary vasospasm, and this should be considered as one of the possible differential diagnoses. We were able to prevent the lethal consequences seen with coronary artery spasm by early diagnosis and management.

Clinical validation of coronary artery flow through an intracoronary shunt during off-pump coronary artery bypass grafting

OBJECTIVES

Intracoronary shunts have been developed for a bloodless field and preserved forward flow preventing ischemia during off-pump coronary artery bypass (OPCAB) surgery. However, reports directly measuring the forward flow through the shunt in clinical settings are lacking.

METHODS

Using a 7.5-MHz Doppler probe, we investigated the coronary flow through a 1.5-mm shunt inserted into the left anterior descending artery (LAD) for anastomosis with the internal thoracic artery during OPCAB in 30 consecutive patients. The following Doppler flow parameters were obtained before and after shunting: peak velocity, mean velocity, time-velocity integral, and flow.

RESULTS

No patients developed significant electrocardiographic changes and the peak value of postoperative myocardial band of creatine kinase was 17 ± 16 IU/L. All Doppler flow parameters of the LAD decreased significantly after shunting; peal velocity: 71.3 ± 34.6 cm/second to 54.5 ± 25.3 cm/second (-24% ± 27%), mean velocity: 33.3 ± 18.3 cm/second to 26.3 ± 14.0 cm/second (-21% ± 23%), and time-velocity integral: 28.7 ± 12.1 cm to 19.0 ± 7.1 cm (-28% ± 14%), and flow: 38.7 ± 16.8 mL/minute to 25.0 ± 9.5 mL/minute (-31% ± 13%) (P < .01).

CONCLUSIONS

The LAD flow is preserved at least 50% through a 1.5-mm intracoronary shunt, although the flow pattern was attenuated, during OPCAB anastomosis. The Doppler evaluation of the coronary artery flow before and after shunting is useful to justify the protective use of the shunt on myocardial perfusion during OPCAB.

Elective minimally invasive coronary artery bypass: shunt or tournique occlusion? Assessment of a protective role of perioperative left anterior descending shunting on myocardial damage. A prospective randomized study

Background

To determine impact of intraluminal-left anterior descending shunt to prevent myocardial damage in minimally invasive coronary artery bypass.

Methods

38 patients were randomly assigned to external tournique occlusion (n = 19) or intraluminal-left anterior descending shunt group (n = 19). Blood samples for cardiac troponin T were collected at 30 minutes prior to, 6 and 24 hours after surgery.

Results

One patient in external tournique occlusion and two patients in intraluminal-left anterior descending shunt group were excluded from futher analysis due to preoperative cardiac troponin T level above the 99th-percentile. Postoperatively, each six patients in external tournique occlusion (33.3%) and intraluminal-left anterior descending shunt (35.3%) group were above the 99th-percentile. Two patients from each group (external tournique occlusion group 11.1% vs. intraluminal-left anterior descending shunt group 11.8%) had peak values above 10-% coeficient of variation cutoff (p = 1). There were no significant differences in between both groups at all studied timepoints.

Conclusion

There was no protective effect of intraluminal shunting on myocardial damage compared to short-term tournique occlusion. It is upon the surgeon's discretion which method may preferrably be used to achieve a bloodless field in grafting of the non-occluded left anterior descending in minimally invasive coronary artery bypass.

Coronary artery bypass grafting without full sternotomy

Coronary artery bypass grafting is performed without full sternotomy in selected patients because it is less invasive. Left internal thoracic artery-left anterior descending artery bypass (LITA-LAD bypass) via a small left anterior thoracotomy is a well established procedure, which achieves good graft patency with low mortality and morbidity rates. Multiple revascularization is possible with a limited lateral thoracotomy or L-figure approach. Axillary-coronary bypass and right gastroepiploic artery-right coronary artery bypass (RGEA-RCA bypass) are alternative methods, especially for redo surgery, in selected patients.

CORONARY ARTERY SPASM AFTER OFF-PUMP CORONARY ARTERY BYPASS GRAFTING

BACKGROUND

Coronary artery spasm (CAS) in the immediate postoperative period has been recognized as a possible cause for perioperative myocardial ischaemia after off-pump coronary artery bypass grafting (CABG). It varies in severity and can be associated with circulatory collapse and death. The purpose of this study was to present our experiences on CAS after off-pump CABG and detail its management.

METHODS

The case reports of three patients with similar clinical presentations of ischaemic heart disease who underwent CABG using an off-pump technique are reviewed. Severe manifestations of CAS in the immediate postoperative period with documented angiographic findings are presented.

RESULTS

Three patients (two men and one woman) with angina pectoris were diagnosed with coronary artery disease using coronary angiography. The elective off-pump CABG was uneventful; however, severe manifestation of myocardial ischaemia with abrupt onset developed at the intensive care unit. All three patients underwent immediate coronary angiography to verify the diagnosis of CAS. Apart from intracoronary nitroglycerine infusion and medical support with inotropic agents, extracorporeal membranous oxygenation was carried out because of severe haemodynamic deterioration in one case, while support was required with intraaortic balloon pumping in another. All three patients made a full recovery.

CONCLUSION

Coronary artery spasm can severely complicate the postoperative course for patients undergoing off-pump CABG, leading to myocardial ischaemia or infarction, life-threatening arrhythmias, persistent hypotension and even cardiac arrest. Early awareness and diagnosis of CAS with the establishment of appropriate management strategies may prevent its potentially lethal consequences.