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The Aortic Valve
Published in Theo Kofidis, Minimally Invasive Cardiac Surgery, 2021
Giovanni Domenico Cresce, Loris Salvador
In the majority of previous reports, minimally invasive AVR is associated with longer operative times compared with standard sternotomy. Several studies have shown that the aortic cross clamp and cardiopulmonary bypass times are considered strong independent predictors of postoperative morbidity and mortality [4,5]. We are aware that building an endoscopic minimally invasive program requires a well-defined learning curve and so, at the beginning, the operative times are longer. We are confident that the operative times can be reduced over time with surgeons’ growing experience and with the further development of sutureless or rapid-deployment valves. In our experience the Perceval valve required significantly shorter cross clamp and CPB times than the Intuity valve and the standard stented bioprosthesis. In E-AVR the Perceval valve seems to be the most comfortable prosthesis to implant, since it is collapsed on its holder and the visualization of the aortic annulus during positioning and deployment is maximized, even though its implantation requires a higher transverse aortotomy, reducing the space for proximal anastomoses.
Critical Care and Anaesthesia
Published in Tjun Tang, Elizabeth O'Riordan, Stewart Walsh, Cracking the Intercollegiate General Surgery FRCS Viva, 2020
Rajkumar Rajendram, Alex Joseph, John Davidson, Avinash Gobindram, Prit Anand Singh, Animesh JK Patel
What are the cardiovascular effects of releasing the aortic cross-clamp?The removal of the aortic cross-clamp is associated with a significant reduction in systemic vascular resistance and a consequent decrease in the mean arterial pressure. The blood vessels in the previously ischaemic areas are severely dilated because of the accumulation of metabolites such as adenosine, lactate, and CO2 during the time of ischaemia. This promotes shift in blood flow and volume into those previously under-perfused areas causing central hypovolaemia. There is subsequently washing off the said metabolites, exacerbating hypotension.Reactive hyperaemia also ensues following unclamping due to smooth muscle relaxation, thus facilitating higher flows in areas after removal of the aortic clamp.Left ventricular end-diastolic pressure decreases significantly and myocardial perfusion increases. However, decreased myocardial contractility may be an issue due to acidosis after prolonged clamping time (increased lactate and PaCO2).The blood flow to area proximal to the clamp site reduces to levels of pre-clamping relatively quickly.
Methods and Procedures
Published in Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin, Brain Injury and Pediatric Cardiac Surgery, 2019
Jane W. Newburger, Wypij David
During the first 24 hours after surgery, hemodynamic status was determined at specified intervals following removal of the aortic cross-clamp. Measurements include cardiac index, systemic and pulmonary resistance, and calculated oxygen consumption. Myocardial and brain isoenzymes of creatine kinase (CK-MB and CK-BB) were measured upon induction of anesthesia; upon reaching 32°C (rectal) during the rewarming phase; and then 1.5, 3, and 6 hours following resumption of bypass. Measurements of CK-BB (in IU/L) were performed by International Immunoassay Laboratories Inc., Santa Clara, California. The study nurse recorded daily medications, respiratory status, laboratory studies, fluid balance, blood and blood product requirements, and significant medical events until hospital discharge.
Effect of different ventilation strategies during cardiopulmonary bypass on cardiac de-airing in congenital cardiac surgery: A trans-esophageal echocardiography comparative study
Published in Egyptian Journal of Anaesthesia, 2022
Salwa M. S. Hayes, Mohamed Magdy, Ghada A. El Rahamawy, Mohamed A. Elgamal, Naglaa A. Elnegeery
After surgical procedure, the de-airing process and weaning from CPB were commenced guided with TEE; if the serum potassium level (k+) was less than 6 mmol/dl, a normal body temperature had been established and the ABG was normal and no cardiac arrhythmia was detected. The lungs were ventilated and de-airing of the LV apex and aortic root was carried out continuously using the vent catheter that was inserted in these locations, and then the aortic cross-clamp was released. The patient was positioned head down, and the surgeon gradually decreased the CPB venous return with gradually filling the heart chambers and de-airing continued while the patient was checked with TEE. De-airing process was carried out until no air emboli were noticed in the left atrium and the heart was allowed to start ejection (pre-ejection de-airing time in seconds before removal of aortic cross clamp). After hemodynamic stability and weaning patient from CPB, TEE monitoring continued till it showed that there were no air emboli in the left side of the heart and the LV vent was stopped (post-ejection de-airing time in seconds). Heparin was reversed with protamine sulphate at a ratio of 1:1.5 to the heparin initial dose to achieve ACT baseline levels. In all patients, hemoglobin was maintained at around 10 gm% postoperatively. Following their transfer to ICU under monitoring, the patients had their chest X-rays taken once every day until their ICU discharge.
Early, Single Center Experience with Ozaki Technique for Aortic Valve Reconstruction
Published in Structural Heart, 2020
Alberto Albertini, Eliana Raviola, Simone Calvi, Alberto Tripodi, Paola Quagliara, Fabio Zucchetta, Elisa Mikus
Results: The mean age was 52.95 ± 14.72 years old (21–74 years, 76.2% male). The predominant pathology was aortic valve stenosis (61.9%) followed by aortic regurgitation (33.3%) and one patient was treated for endocarditis (4.7%). Nine patients (42.8%) presented with a bicuspid aortic valve and in one patient a monocuspid valve was found. Concomitant procedures included: coronary arteries by-pass grafts (5 patients, 23.8%), ascending aorta replacement (1 patient, 4.7%), mitral valve valvuloplasty (5 patients, 23.8%), interventricular septal myectomy (1 patient, 4.7%). The mean aortic cross-clamp time and cardiopulmonary bypass time were respectively 131.95 and 119.57 minutes. All patients have been extubated (mean intubation time 9.76 ± 4.99 hours) and intensive care unit and hospital stay was respectively 2.5 ± 1.25 and 6.10 ± 4.68 days. There was no in-hospital mortality. Transthoracic echocardiography showed a peak aortic pressure gradient of 14.09 ± 7.62 mmHg and a mean aortic pressure gradient of 7.91 ± 3.33 mmHg. Aortic valve regurgitation was trivial in 8 patients (38%) and no valve stenosis was detected.
Acute type A aortic dissection – a review
Published in Scandinavian Cardiovascular Journal, 2020
Tomas Gudbjartsson, Anders Ahlsson, Arnar Geirsson, Jarmo Gunn, Vibeke Hjortdal, Anders Jeppsson, Ari Mennander, Igor Zindovic, Christian Olsson
Surgical treatment of ATAAD cannot be truly evidence-based. The advantages and disadvantages of each permutation of cannulation, perfusion, and surgical repair remain. Often, a conservative approach, using femoral artery cannulation, HCA with any form of cerebral perfusion, and a supracoronary graft replacing the dissected ascending aorta will suffice and provide the safest alternative. Even repair under aortic cross-clamp cannot be rejected outright, based on the data available. Still, unique patient and dissection characteristics must be recognized and, if necessary, influence strategy. If a risk of malperfusion through the femoral artery is envisioned or detected, an alternative arterial cannulation site should be chosen. Younger patients, or patients with connective tissue disease, may benefit most from valve-sparing aortic root repair (which, notably, can be undertaken during rewarming and may not necessarily prolong CPB time or procedural time). Arch inspection during HCA may reveal a longitudinal tear motivating arch replacement, in turn an impetus for meticulous cerebral perfusion and protection, allowing ample time for repair. Thus, optimal management of a wide spectrum of ATAAD patients requires surgical adaptation and versatility, which is provided more and more often in dedicated aortic centres and is often associated with documented improvement in outcomes [86].