invited commentary
TRANSCRIPT
123Ann Thorac Surg KUNKALA ET AL2014;97:118–23 MYOCARDIAL BRIDGE UNROOFING AT MYECTOMY
ADULTCARDIA
C
obstructive hypertrophic cardiomyopathy. J Am Coll Cardiol2005;46:470–6.
25. Alima MB, Vanden Eynden F, Preumont N, Jansens JL. Ro-botic-assisted surgical myotomy in a 27-year-old man withmyocardial bridging of the left anterior descending coronaryartery. Interact Cardiovasc Thorac Surg 2010;11:185–7.
� 2014 by The Society of Thoracic SurgeonsPublished by Elsevier Inc
26. Xu Z, Wu Q, Li H, Pan G. Myotomy after previous coronaryartery bypass grafting for treatment of myocardial bridging.Circulation 2011;123:1136–7.
27. Stables RH, Knight CJ, McNeill JG, Sigwart U. Coronarystenting in the management of myocardial ischaemia causedby muscle bridging. Br Heart J 1995;74:90–2.
INVITED COMMENTARY
The prevalence of myocardial bridging is reported torange from 0.5% to 30% and is more frequently found inpatients with hypertrophic obstructive cardiomyopathy(HCM) [1]. The “milking effect” seen on angiographyduring systole is considered a benign condition becausearteries are irrigated during diastole. However, somegroups have shown that this narrowing effect could beextended to diastole [2]. Clinically, myocardial bridgingmay be associated with myocardial ischemia, tachycardia-induced ischemia, conduction abnormalities, myocardialinfarction, and even sudden death [3]. Although clinicalstudies have shown that myocardial bridging is an inde-pendent risk factor for developing myocardial ischemiaand interstitial fibrosis [4], prognostic data are limited.
Because the severity of the wall thickness is moreimportant in patients with HCM, Kunkala and associates[5] evaluated the clinical outcome of muscular bridgeunroofing of the left anterior descending artery at thetime of septal myomectomy in patients with HCM. Thisretrospective study compared three groups of patients:group 1, myomectomy and unroofing; group 2, myo-mectomy alone; and group 3, no surgical intervention.The results showed that myocardial unroofing can beperformed safely. Angina was improved in group 1 but nodifference was found in terms of late survival. This groupreported their experience of myocardial unroofing duringseptal myomectomy as guidance to clinical decisionmanagement. Myocardial bridging is still controversial inthe literature even on the pathophysiologic side and onthe symptomatic relief and clinical prognosis of thisintervention.
This paper by Kunkala and colleagues [5] is of someinterest because of the rarity of the condition, but thereare many shortcomings inherent to the nature of thestudy that prevent us from obtaining definitive answers.In particular, very few data are given concerning thephysiopathologic consequences of bridging in these
patients or in patients without HCM and bridging. Thereis no documentation of ischemia in the anterior territory,no explanation for recurrence of angina. Numerousdetails are lacking concerning anatomy of the bridge,findings at angiography, and medical management ofpatients. The risks of unroofing being small, perhaps itshould be recommended for all (with or without angina)at the time of myomectomy. Further studies should beconsidered to reinforce the link between the clinicalsymptoms and the pathophysiologic mechanism, becausethe paradox remains.
Jessica Forcillo, MD, MSLouis P. Perrault, MD, PhD
Department of Surgery, Research CenterMontreal Heart Institute5000 Belanger StMontreal, PQ H1T 1C8, Canadae-mail: [email protected]
References
1. Marshall ME, Headley RN. Intramural coronary artery as acause of unstable angina pectoris. South Med J 1978;71:1304–6.
2. Bourassa MG, Butnaru A, Lesperance J, Tardif JC. Symp-tomatic myocardial bridges: overview of ischemic mecha-nisms and current diagnostic and treatment strategies. J AmColl Cardiol 2003;41:351–9.
3. Bestetti RB, Costa RS, Zucolotto S, Oliveira JS. Fatal outcomeassociated with autopsy proven myocardial bridging of the leftanterior descending coronary artery. Eur Heart J 1989;10:573–6.
4. Brodsky SV, Roh L, Ashar K, Braun A, Ramaswamy G.Myocardial bridging of coronary arteries: a risk factor formyocardial fibrosis? Int J Cardiol 2008;124:391–2.
5. Kunkala MR, Schaff HV, Burkhart H, et al. Outcome of repairof myocardial bridging at the time of septal myectomy. AnnThorac Surg 2014;97:118–23.
0003-4975/$36.00http://dx.doi.org/10.1016/j.athoracsur.2013.08.004