Detrimental effects of elevated transpulmonary gradient on outcomes following restrictive mitral annuloplasty in patients with pre-existing pulmonary hypertension

Satoshi Kainuma; Koichi Toda; Shigeru Miyagawa; Yasushi Yoshikawa; Hiroki Hata; Daisuke Yoshioka; Takuji Kawamura; Ai Kawamura; Noriyuki Kashiyama; Takayoshi Ueno; Toru Kuratani; Toshihiro Funatsu; Haruhiko Kondoh; Takafumi Masai; Arudo Hiraoka; Taichi Sakaguchi; Hidenori Yoshitaka; Takashi Daimon; Kazuhiro Taniguchi; Yoshiki Sawa; Osaka Cardiovascular Surgery Research (OSCAR) Group

doi:10.21037/jtd-20-2898

Detrimental effects of elevated transpulmonary gradient on outcomes following restrictive mitral annuloplasty in patients with pre-existing pulmonary hypertension

J Thorac Dis. 2021 May;13(5):2746-2757. doi: 10.21037/jtd-20-2898.

Authors

Satoshi Kainuma^{1

2}, Koichi Toda¹, Shigeru Miyagawa¹, Yasushi Yoshikawa¹, Hiroki Hata¹, Daisuke Yoshioka¹, Takuji Kawamura¹, Ai Kawamura¹, Noriyuki Kashiyama¹, Takayoshi Ueno¹, Toru Kuratani¹, Toshihiro Funatsu², Haruhiko Kondoh², Takafumi Masai³, Arudo Hiraoka⁴, Taichi Sakaguchi⁴, Hidenori Yoshitaka⁴, Takashi Daimon⁵, Kazuhiro Taniguchi², Yoshiki Sawa¹; Osaka Cardiovascular Surgery Research (OSCAR) Group

Affiliations

¹ Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
² Department of Cardiovascular Surgery, Japan Organization of Occupational Health and Safety Osaka Rosai Hospital, Sakai, Osaka, Japan.
³ Department of Cardiovascular Surgery, Sakurabashi Watanabe Hospital, Osaka, Osaka, Japan.
⁴ Department of Cardiovascular Surgery, Sakakibara Heart Institute of Okayama, Okayama, Japan.
⁵ Department of Biostatistics, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.

Abstract

Background: This study retrospectively examined the association between elevated trans-pulmonary gradient (TPG), which reflects pre-capillary contribution to pulmonary hypertension (PH), and postoperative pulmonary hemodynamics and outcomes following restrictive mitral annuloplasty (RMA) in patients with pre-existing PH.

Methods: Pre- and postoperative (1 month) cardiac catheterization was performed in 64 patients with severely impaired left ventricular function (i.e., ejection fraction ≤40%) and pre-existing PH (mean pulmonary artery pressure (PAP) ≥25 mmHg) who underwent RMA. Patients were segregated into two groups: low TPG (≤12 mmHg) and elevated TPG (>12 mmHg). The mean follow-up period was 54±27 months. The primary outcome seen was a change in pulmonary hemodynamics after RMA; secondary outcomes were composite adverse events, including all-cause mortality and readmission for heart failure.

Results: Compared to the low TPG group, patients in the elevated TPG group were more likely to show a postoperative mean PAP of ≥25 mmHg (84% vs. 38%), TPG of >12 mmHg (79% vs. 11%), and pulmonary vascular resistance of ≥240 dynes/sec/cm^-5 (84% vs. 6.7%) (all P<0.001), although both groups showed comparable degrees of mitral regurgitation improvement. Serial echocardiography demonstrated that Doppler-derived systolic PAP, which once decreased in both groups, remained stable in the low group while steadily increasing in the elevated group (group effect P<0.001). Patients with elevated TPG had lower freedom from composite adverse events (5-year, 20% vs. 70%, P=0.003). After adjusting for baseline covariates, the elevated TPG was independently associated with increased risk of adverse events (adjusted hazard ratio 2.9, 95% CI: 1.2-6.9, P=0.017).

Conclusions: Elevated TPG negatively affects postoperative pulmonary hemodynamics and late outcomes in patients with advanced cardiomyopathy and pre-existing PH who have undergone RMA. These findings suggest that the assessment of TPG should be included in post-RMA risk stratification.

Keywords: Cardiomyopathy; heart failure; pulmonary hypertension; pulmonary vascular remodeling; restrictive mitral annuloplasty (RMA).