Is pulmonary artery pressure a trigger of adverse outcome in mitral regurgitation?

Iside Scarfò, Giovanni La Canna


Mitral regurgitation (MR) is an important cause of morbidity and mortality in developed countries (1,2). The most common cause of MR is degenerative with an age-related epidemiological burden consisting of a peak incidence in patients over 70 years of age (1). Open surgical correction, using mitral valve repair or replacement, is currently accepted as the standard treatment of MR. Congestive heart failure symptoms or left ventricular (LV) dysfunction (EF <60% or end-systolic diameter >40 or >45 mm according to ACC/AHA and ESC guidelines, respectively) are the suggested Class-I triggers for surgery (3,4). However, surgical treatment based on Class-I triggers may be characterized by a suboptimal postoperative outcome. Due to its long standing asymptomatic clinical course, the selection of optimal timing for surgery remains an important challenge (5-7). Due to the absence of randomized studies, current guidelines are based on the inference from observational studies or expert opinions. An ESC-position paper supports the organization of specialized valve clinics attempting optimal and individualized MR management (8). In the last few decades, the wide application of mitral valve repair has progressively changed the timing for surgery in patients with MR. Targeting valve lesion treatment, independent of symptoms and LV deterioration signs, mitral valve repair challenges the more conservative valve replacement approach, leading to early surgery in order to achieve an optimal postoperative outcome. The key points to consider are the predictability of repair using the best surgical strategy based on the functional mechanism of MR, the evaluation of MV repair efficacy before closing the chest, prediction and management of complications, and radicalization of MR treatment to achieve a durable repair without longterm recurrence or lesion progression. Mitral valve repair has been proposed for the treatment of MR without Class-I triggers when functional mitral anatomy matched with an experienced surgical team predicts a 95% rate of successful and durable repair with an expected surgical mortality <1%. Unlike the ACC/AHA statement, decision-making based on surgical reparability alone is not considered beneficial in the ESC recommendations (Class IIb). Although repair feasibility is considered a key point for early surgery in the real world the ultimate repair of degenerative MR is around 60%, with great inter-hospital variability related to team experience and intervention volume rate. The use of three-dimensional imaging may improve communication with surgeons, enabling them to predict a surgical strategy that might help close the gap between valve reparability and ultimate repair. New onset atrial fibrillation or resting pulmonary hypertension (PH) may be the facilitators of decision-making to perform mitral repair in asymptomatic MR with preserved LV function (Class IIa).