Aortic regurgitation in coronary artery bypass grafting: implications for cardioplegia administration

Mitigating cardiac dysfunction by TOE-guided cardioplegia and mitral valve repair

Based on current guidelines, 15% to 20% of patients undergoing mitral valve repair for regurgitation develop left ventricular dysfunction (ejection fraction < 50%-55%) despite a normal baseline. Two schools of thought have been debated: preexisting myocardial disease or suboptimal intraoperative myocardial protection. In our view, they could be reconciled. It is well recognized that left ventricular ejection fraction with a standard cut off at 50%-55% has limited sensitivity in detecting early systolic impairment in mitral regurgitation patients. Mitral regurgitation also leads to mitochondrial oxidative stress, thus rendering the myocardium more susceptible to ischemia-reperfusion injury and precipitating postoperative cardiac dysfunction. The fall in left ventricular ejection fraction early after mitral valve repair was shown to be caused by the reduction in both myocardial contractility and left ventricular stroke volume. To mitigate the risk to myocardial reperfusion injury, appropriate cardioplegia volume and distribution and well-defined surgical repair processes are equally important. We use transesophageal echocardiography-guided cardioplegia delivery, imaging the intramyocardial flow and ensuring adequate protection of the subendocardium during mitral valve repair. Mild aortic regurgitation on a beating heart often leads to left ventricular dilatation with diminished cardioplegia flow in the myocardium, thus requiring direct ostia cardioplegia. Systematic transesophageal echocardiography assessment before surgery is essential for establishing the mitral regurgitation mechanisms and translating them into precise surgical repair strategies. The benefits of transesophageal echocardiography-guided cardioplegia delivery warrant further clinical trials in order to evolve into part of a high surgical standard.

Intraoperative transesophageal echocardiography in cardiovascular surgery. Consensus document from the Spanish Society of Anesthesia and Critical Care (SEDAR) and the Spanish Society of Endovascular and Cardiovascular Surgery (SECCE)

Transesophageal echocardiography is a semi-invasive technique that allows an evaluation of cardiac morphology and function in real time and it is a quality standard in cardiovascular surgery. It has become a fundamental tool for both monitoring and diagnosis in the intraoperative period that allows decide the correct surgical planning and pharmacological management. The goal of this document is to answer the questions of when and how the perioperative TEE should be performed in cardiovascular surgery, what are their applications in the intraoperative, who should perform it and how the information should be transmitted. The authors made a systematic review of international guidelines, review articles and clinical trials to answer by consensus to these questions.

Intraoperative echocardiography in valvular heart disease: an evidence-based appraisal

Intraoperative (IO) transesophageal echocardiography (TEE) is widely used for assessing the results of valvular heart disease (VHD) surgery. Epiaortic ultrasonography (EAU) has been recommended for prevention of perioperative strokes. To what extent does high-quality evidence justify the widespread use of these imaging modalities? In March 2009, we searched MEDLINE (PubMed and OVID interfaces) and EMBASE for studies published in English using database-specific controlled vocabulary describing the concepts of IOTEE, cardiac surgery, VHD, and EAU. We found no randomized trials or studies with control groups assessing the impact of IOTEE in VHD surgery. Pooled analysis of 8 observational studies including 15,540 patients showed an average incidence of 11% for prebypass surgical changes and 4% for second pump runs, suggesting that patients undergoing VHD surgery may benefit significantly from IOTEE, particularly from postcardiopulmonary bypass IOTEE in aortic repair and mitral repair and replacement, but less so in isolated aortic replacement. Further available indirect evidence was satisfactory in the test accuracy and surgical quality control aspects, with low complication rates for IOTEE. The data supporting EAU included 12,687 patients in 2 prospective randomized studies and 4 nonrandomized, controlled studies, producing inconsistent outcome-related results. Despite low-quality scientific evidence supporting IOTEE in VHD surgery, we conclude that indirect evidence supporting its use is satisfactory and suggests that IOTEE may offer considerable benefit in valvular repairs and mitral replacements. The value of IOTEE in isolated aortic valve replacement remains less clear. Evidence supporting EAU is scientifically more robust but conflicting. These findings have important clinical policy and research implications.

A technique for infusion of cardioplegic solution in coronary artery bypass with aortic regurgitation

BACKGROUND

Complications such as heart failure due to insufficient cardioplegia may develop in on-pump coronary artery bypass (CAB) with mild-to-moderate aortic regurgitation (AR). A technique for administration of cardioplegic solution was carried out to avoid such complications.

METHODS AND RESULTS

Cardiopulmonary bypass was established. After aortic cross-clamping, cardioplegic solution was administered from aortic root. Because complete cardiac arrest was not rapidly achieved, the aortic root was incised. Three cusps of the aortic valve were sutured. The aorta was closed; cardioplegic solution was administered from the aortic root. Then, cardiac arrest was rapidly achieved. After distal anastomosis of quadruple bypass was completed, the suture of the cusps was removed. There was no exacerbation of AR due to this method compared to the preoperative state.

CONCLUSION

When off-pump coronary artery bypass is impossible and retrograde cardioplegia cannot be performed for a certain reason, this method may be set to one of the choices.