Technical tips for Reducing the Risk of Atrioventricular Disruption Following Mitral Valve Replacement
M.Marzban MD and P.Benharash MD
Mehrab Marzban, MD. Peyman Benharash,MD
Cardiovascular Outcomes Research Laboratories, Division of Cardiac Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California
Corresponding author: Mehrab Marzban,MD
Email:MMarzban@mednet.ucla.edu
10833 Le Conte Ave.62-249 CHS
Los Angeles, CA 90095
Abstract
This report describes the effective measures in order to prevent the devastating complication of AV groove disruption following mitral valve replacement.
Ethics committee approval, consent statement and clinical trial registration are not applicable for our study.
Introduction
Rupture of the Atrioventricular (AV) groove or in a broader sense, left ventricular rupture is a n infrequent but often fatal complication of mitral valve replacement. Treasure and colleagues were the first to define this entity in 1973 in 7 patients. (1) In 1980, Cobb et al described the complication as “transverse midventricular disruption. “The authors also pointed out that a false aneurysm could be the end result of an incomplete rupture. Although AV groove rupture was reported in up to 14% of cases in the early years of valve replacement, refined surgical techniques and lower profile prostheses have reduced its incidence to 0.5-2% in modern series (2).
While the exact mechanism responsible for this complication was initially unclear, several risk factors including redo operations, severe annular calcification, advanced age, hemodialysis dependence, and resection of posterior leaflet and apparatus, appear to increase the likelihood of AV groove disruption. Preexisting intrinsic myocardial disease, especially ischemia, rheumatic myocarditis, and infectious processes have also been implicated. (3) Rupture is most commonly noted in the operating room or in the early postoperative period and may be often preceded by a period of systemic hypertension. There are several reports of late presentation as a pseudo aneurysm of the left ventricle or delayed rupture in the literature. (5) notwithstanding the favorable outcomes of few investigators such as Tirone E. David (6), the fatality of this complication appears to be in excess of 75%. (7). If rupture occurs outside of the operating room, the chances of successful recovery are negligible. Thus, every attempt should be made to prevent rupture from happening. Below, we provide several technical considerations that, in our experience, have reduced the risk of AV groove disruption.
Technique:
Exposure:
At first, it is essential to identify the high-risk patient based on the preoperative evaluation. Every patient who has an MVR is a potential candidate for AV groove complication and every effort should be made to avoid it, but there is some extra caution which is required in high-risk groups.
Good exposure
good exposure of the mitral valve is of paramount importance to avoid this complication especially in patients who are obese or have barrel chest when the LA is small and also in redo surgery. Pericardial adhesion from the previous operation or rheumatic pancarditis may limit heart mobility, in this situation, exposing the mitral valve, excising the degenerated valve, and putting the annular sutures require excessive traction on the annulus that may lead to subtle or obvious damage to the ventricular wall. As a result, it is advisable to mobilize the heart completely from pericardial adhesion. On the other hand, based on the surgeon’s experience, a proper approach like the trans-septal approach may be preferred to address the mitral valve.
.
Chordal sparing
Preservation of posterior leaflet and apparatus: Excision of posterior leaflet and subvalvular apparatus has been suggested as a major contributing factor for AV groove damage. (8) Thus it is prudent to preserve the annulo-papillary continuity as much as possible. In some occasions, due to severe mitral annular calcification, it is inevitable to resect the posterior leaflet, even in this situation the papillary muscles should be reattached to the corresponding posterior annulus either directly by annular sutures or using artificial chordae. This surgical tip leads to less impairment of left ventricular function and minimizing the risk of ventricular rupture There are different methods for annular decalcification based on the calcification severity and extension, furthermore, the surgeon’s experience has a definitive role. It can be a piecemeal or en bloc resection associated with annular reconstruction using autologous or bovine pericardium. Either technique needs a meticulous dissection, overzealous decalcification should be avoided.
Undersizing the prosthesis
Another important measure is undersizing the prosthesis when the patient is assumed to be at high risk for AV groove disruption. The oversized prosthesis has been mentioned as a risk factor for the dreaded complication of AV groove rupture (9) but, we put our step beyond that, our recommendation is to undersizing the prosthesis to reduce the pressure of the prosthesis cuff on the muscle fibers of the AV groove.
Interrupted pledgetted sutures
Despite several reports on the safety of continuous suture technique in mitral valve replacement, we believe that continuous suturing has potentially more risk of damage to the annulus due to the excessive traction which is needed for suture placement especially if the exposure is not optimal. Interrupted sutures provide more secure and reinforced sutures in severe annular calcification.
Avoidance of inotrope and volume overload
Forceful contraction of the left ventricle against the rigid cuff of the valve prosthesis has been implicated in the pathogenesis of AV groove disruption following MVR. Most patients after MVR do not require inotropic support and can be weaned from CPB without difficulty. Unnecessary use of inotropes should be abandoned. Volume overload and the chamber distention may contribute to muscle fiber separation in AV groove and should be avoided.
Avoidance of heart massage or tapping on the heart for desiring
There are different methods to deair the heart chambers before the termination of CPB. Some surgeons used to fill the heart while resuming the ventilation and squeezing the heart whereas it has the potential to damage the heart and should be discouraged after mitral valve replacement.
Comment
Following these simple measures in 437 patients with mitral valve replacement, luckily we did not encounter this dreaded complication.
References
1.Treasure R.L.,Rainer W.G.,Strevey T.E.,Sadler T.R.
Intraoperative left ventricular rupture associated with mitral valve replacement.
Chest. 1974; 66: 511-514
2. Cobb BW, Hatcher CR, Craver JM, Jones EL, Sewell CW:
Transverse midventricular disruption after mitral valve replacement.
Am Heurt J 99, 33-50 (1980
3. Spencer FC, Galloway AC, Colvin SB. A
clinical evaluation of the hypothesis that rupture of the left ventricle following mitral valve replacement can be prevented by preservation of the chordae of the mural leaflet.
Ann Surg. 1985;202(6):673–80.
4. Hosono M, Shibata T, Sasaki Y, et al. Left ventricular rupture after mitral valve replacement: risk factor analysis and outcome of resuscitation. J Heart Valve Dis. 2008;17(1):42–7.
5. Ciro Mancilha Murad, Letícia Braga Ferreira, Rochelle Coppo Militão Rausch, Cláudio Léo Gelape
Late atrioventricular groove disruption presenting 7 years after mitral valve replacement: a case report
European Heart Journal - Case Reports, Volume 4, Issue 3, June 2020, Pages 1–5,
6. Tirone E. David, MD. Left ventricular rupture after mitral valve replacement
JTCVS Open 2020;3:48-9
7.Karlson KJ, Ashraf MM, Berger RL: Rupture of left ventricle following mitral valve replacement. Ann Thorac Surg. 1998, 46: 590-597.
8.Jin-Tae Kwon, Tae-Eun Jung & Dong-Hyup Lee
The rupture of atrioventricular groove after mitral valve replacement in an elderly patient
J Cardiothorac Surg 9, 28 (2014)
9.Makoto Kamada 1, Kenji Ohsaka, Susumu Nagamine, Hidemitsu Kakihata
Left ventricular rupture following mitral valve replacement due to oversize prosthesis
Jpn J Thorac Cardiovasc Surg 2004 Dec;52(12):589-91.
10. Dark JH, Bain WH. Rupture of posterior wall of left ventricle after mitral valve replacement. Thorax. 1984;39(12):905–11