Mitral Valve Surgery: Effects on Cardiac Reverse Remodeling, Hemodynamics, and Clinical Outcome

Abstract: Normalization of life expectancy after mitral valve surgery is highly dependent on early diagnosis and referral for surgical treatment. Among cases treated surgically, the majority (60–70%) have a degenerative etiology, which is also easiest to repair. The general aim of this thesis was to bring research on treatment of degenerative mitral regurgitation a step further in order to improve clinical outcome after mitral valve surgery. Patients recruited for the four studies all underwent mitral valve surgery at the Department of Cardiothoracic Surgery, Anesthesia and Intensive Care, Skåne University Hospital, Lund, Sweden. Left atrial enlargement has been identified as a marker of adverse clinical outcome in chronic severe mitral regurgitation. The extent of postoperative left atrial reverse remodeling (LARR) may be of clinical relevance, considering the relationship between left atrial enlargement and survival, heart failure, atrial fibrillation, and stroke. The first and second studies (Papers I and II) showed that most of the patients had LARR following surgery. Absence of LARR was associated with higher age (≥ 60 years), was predicted by a high preoperative left atrial volume, and did not influence survival or occurrence of new-onset chronic atrial fibrillation during follow-up. The third study (Paper III) showed that patients with severe left atrial enlargement had high mean baseline pulmonary capillary wedge pressure, which normalized early after mitral valve repair. The fourth study (Paper IV) demonstrated that right ventricular dysfunction was common. Pulmonary hypertension, although reversible after surgery, had a negative effect on right ventricular function. In conclusion, severe left atrial enlargement is highly reversible following mitral valve surgery and may reflect preoperative cardiac remodeling. A systematic echocardiographic assessment may identify early signs of remodeling due to chronic degenerative mitral regurgitation, may assist in the prioritization of surgical referrals, and may facilitate perioperative management.