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The Mitral Valve
Published in Theo Kofidis, Minimally Invasive Cardiac Surgery, 2021
Nirav C Patel, Meghan K Torres, Jonathan M Hemli
Right-lung isolation is typically facilitated through the use of a double-lumen endotracheal tube, although a bronchial blocker could potentially be utilized instead. We find that the former option provides more reliable and consistent lung deflation. After endotracheal intubation, a 17-Fr cannula is percutaneously inserted via the right internal jugular vein into the superior vena cava (SVC), using a standard Seldinger technique, the position of the cannula being confirmed by transesophageal echocardiography. Although not necessarily always mandatory for minimal-access mitral valve surgery, we find the SVC cannula to be invaluable in ensuring adequate venous drainage for cardiopulmonary bypass. This is particularly so, given that our preferred method of attaining cardiac arrest is through the use of a trans-thoracic aortic cross-clamp. We have found that, without an SVC cannula in place, a long aortic cross-clamp, coupled with superior retraction of the roof of the left atrium, can potentially “kink” the SVC, partially obstructing venous return from the cerebrum and upper body, resulting in inadequate venous drainage (Figure 9.3.4 and Figure 9.3.5).
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.
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
In terms of extent of the surgical repair, the supracoronary graft with aortic valve resuspension is the most prevalent and also the most conservative alternative. When the intimal tear extends into the root, if the aortic root is aneurysmatic, or if there is uncertainty regarding the aortic valve integrity and competence of the aortic valve, the root should be replaced. This can be done as a composite graft (biological or mechanical) or as a valve-sparing aortic root repair (VSARR). Patients with known or suspected connective tissue disease will probably benefit from primary aortic root replacement [74]. Distally, the surgical alternatives are numerous. A simple end-to-end anastomosis to the distal ascending aorta, with or without an aortic cross-clamp in place, is at the conservative extreme. A hemiarch replacement, including the lesser curvature of the arch, would be advocated by most; it is more radical but still comparatively comfortable and safe to perform (Figure 4(b)). Arch replacement entails reimplantation of one or more cervical vessels. Reimplantation can be performed as a Carrell patch or by individual grafts, or a combination. Arch replacement can be supplemented by an elephant trunk, a 10–15 cm long vascular prosthesis to direct flow preferentially into the true lumen. If the true lumen is compressed, a stent-graft (so called frozen elephant trunk) is preferable. Dedicated combined, hybrid, stent-graft and vascular prostheses are available. In effect, arch replacement of any kind is certainly more challenging and time-consuming.
Comparison Between Conventional and Minimally Invasive Mitral Valve Surgery. A Brazilian Single-center Experience
Published in Structural Heart, 2019
Carlos M. Brandao, Elinthon T. Veronese, Pablo M. Pomerantzeff, Marcio S. Lima, Flavio Tarasoutchi, Ludmilla A. Hajjar, Fabio B. Jatene
Methods: We performed a retrospective analysis of 67 patients referred to our institution for mitral valve surgery between July 2014 and July 2017. Inclusion criteria were isolated mitral valve disease, normal left ventricular ejection fraction and absence of pulmonary hypertension. Exclusion criteria were reoperations, peripheral vascular disease, ischemic mitral disease, obesity and chest abnormalities. Forty patients were eligible for video-assisted minimally invasive mitral surgery. The other 27 patients were submitted to conventional mitral surgery. Mean EuroSCORE 2 was 0.87%. The minimally invasive approach was performed by right anterior mini-thoracotomy (6.0cm) in the fourth intercostal space with venous and arterial femoral cannulation and the conventional approach by median sternotomy with central cannulation. The procedures were performed by the same surgical team in a standard approach with mild hypothermia and cold blood cardioplegia. The following variables were analyzed: operative mortality, cardiopulmonary bypass and aortic cross-clamp time and postoperative complications (neurologic and renal dysfunction, atrial fibrillation, hemotransfusion, wound infection, reoperation for bleeding and vascular complications). Statistical analysis was performed with Fisher’s Exact Test or T-Test.