Aortic valve visualization and pressurization device: a novel device for intraoperative evaluation of aortic valve repair procedures.

OBJECTIVES: Aortic valve repair procedures are technically challenging, and current intraoperative evaluation methods often fail to predict the final echocardiographic result. We have developed a novel intraoperative aortic valve visualization and pressurization (AVP) device, enabling valve inspection under physiological conditions, and measuring aortic valve insufficiency (AI) during cardioplegic arrest. METHODS: The AVP device is attached to the (neo)aorta, after any type of aortic valve repair, while the heart is arrested. The root is pressurized (60-80 mmHg) using a saline solution and an endoscope is introduced. The valve is inspected, and the amount of valvular leakage is measured. Postoperative 'gold standard' transesophageal echocardiogram measurements of AI are performed and compared against regurgitation volume measured. RESULTS: In 24 patients undergoing valve-sparing root replacement, the AVP device was used. In 22 patients, postoperative echocardiographic AI was ≤ grade 1. The median leakage was 90 ml/min, IQR 60-120 ml/min. In 3 patients, additional adjustments after visual inspection was performed. In 2 patients, with complex anatomy, the valve was replaced. In one, after evaluation with the device, there was undesirable result visually and residual AI of 330 ml/min, and in another, 260 ml/min residual AI was measured and valve restriction on visual inspection. CONCLUSIONS: The novel AVP device enables intraoperative evaluation of the valve under physiological conditions, while still on arrested heart, and allows for targeted adjustments. The AVP device can be an important aid for intraoperative evaluation of the aortic valve, during valve repair and valve-sparing procedures, thereby making the operative result more predictable and the operation more efficient.

Laser speckle contrast analysis for quantifying the Allen test: a feasibility study.

BACKGROUND AND OBJECTIVE: The radial artery has become a routinely used conduit for coronary artery bypass graft surgery (CABG). Prior to surgery the Allen test is performed to test the patency of the ulnar artery. A positive Allen test, reperfusion >5 seconds, suggests an insufficient perfusion of the hand by the ulnar artery. In this study we investigated if laser speckle contrast analysis (LASCA) provides an objective determination of the reperfusion time. MATERIALS AND METHODS: When the hand is illuminated with coherent laser light, the backscattered light will result in an interference pattern consisting of bright and dark areas called speckles. This speckle pattern will change due to movement of red blood cells. LASCA uses these changes to visualize the perfusion during the Allen test. Reperfusion is measured on the palmar side of the hand. The reperfusion time is defined as the time from onset of reperfusion to maximum perfusion calculated by a polynomial curve fit. The reperfusion time of the hand of patients undergoing CABG (n = 30) is measured using LASCA and is compared to the conventional Allen test performed by the nurse practitioner. RESULTS: LASCA measurements showed a negative Allen test of both hands of 16 patients. Fourteen had a borderline reperfusion time of 5-6 seconds and/or a positive Allen test of one or both hands. No statistical significant difference was observed for the LASCA Allen test compared to the conventional Allen test, P = 0.549 for the left hand and P = 0.223 for the right hand. CONCLUSION: LASCA is able to visualize perfusion of the hand and measure a quick, moderate, slow reperfusion response or no reperfusion. It is technically feasible to determine the reperfusion time of the hand. LASCA can be a useful and objective tool to assess ulnar collateral blood supply to the hand prior to harvesting of the radial artery as a bypass graft.

Adventitial dissection: a simple and effective way to reduce radial artery spasm in coronary bypass surgery.

OBJECTIVES: Over the last two decades, the radial artery (RA) has become a routinely used conduit for coronary artery bypass graft surgery. One potential disadvantage of the radial artery is its higher susceptibility to vasospasm compared with other arterial grafts. We investigated whether adventitial dissection of the radial artery can reduce vasoconstriction and increase free blood flow. METHODS: Following harvesting, the adventitia of the radial artery was dissected using coronary scissors. Surplus distal radial artery segments (n = 35) with and without adventitial dissection of patients undergoing coronary artery bypass surgery were collected and pairwise assessment of vasoreactivity to potassium chloride, U46619 and acetylcholine was performed in organ bath experiments. Free blood flow was measured before and after adventitial dissection. RESULTS: Full curve and maximal vasoconstriction of the RA to potassium chloride (P = 0.015 and 0.001) and U46619 (P = 0.048 and 0.001) was significantly reduced after adventitial dissection compared with non-adventitial dissected radial arteries. Endothelium-dependent relaxation to acetylcholine of adventitial dissected radial arteries was significantly increased (P = 0.006) compared with non-adventitial dissected radial arteries. Maximal vasorelaxation to acetylcholine was significantly increased for adventitial dissected radial arteries compared with non-adventitial dissected radial arteries (P = 0.018). Free blood flow was significantly increased after adventitial dissection (P = 0.037). CONCLUSIONS: The adventitial dissected radial artery is less susceptible to vasoconstriction and more prone to vasorelaxation ex vivo and shows an increased free blood flow. Therefore, we suggest adventitial dissection of the radial artery graft to reduce vasospasm for arterial revascularization in coronary artery bypass surgery.