Diastolic function: a barometer for cardiovascular risk?

PERIOPERATIVE cardiovascular risk assessment has undergone significant advances, including development and validation of multivariable risk indices for prediction of major cardiac complications, advances in detecting ischemic heart disease, and noninvasive detection of symptomatic reductions in left ventricular (LV) ejection fraction. However, we have recently recognized that current preoperative assessments may fail to fully appreciate a patient’s vulnerability after a major noncardiac surgery, because early and late cardiac events can occur in the absence of coronary artery disease or heart failure symptoms. In this issue of ANESTHESIOLOGY, Flu et al. extend these findings, identifying the effect that subclinical LV systolic and diastolic dysfunction (DD) has on postoperative outcomes in patients undergoing open vascular or endovascular surgery. Because the current American College of Cardiology/American Heart Association perioperative guidelines fall short in discussing the clinical implications of DD, a closer look at this disorder is warranted. Diastolic dysfunction and diastolic heart failure are not synonymous. The former refers to a preclinical state involving abnormalities in cardiac filling, which result from a combination of slowed LV relaxation and increased stiffness, usually associated with hypertension, diabetes, or ischemia. In contrast, diastolic heart failure, also called heart failure with normal ejection fraction, is the presence of signs and symptoms of heart failure with a normal ejection fraction ( 50%), in the absence of significant valvular and pericardial disease, usually with echocardiographic or angiographic evidence of DD. Diastolic heart failure is a true heart failure syndrome, producing nearly identical signs and symptoms, as well as alterations in neurohormonal activation and impairments in exercise tolerance and exercise cardiac output, similar to those with heart failure associated with reduced ejection fraction. Diastolic dysfunction is also a real disorder that merits clinical recognition, prevention, and treatment. Asymptomatic DD is common in the general population, even in patients without heart failure, it increases with age and is particularly prevalent among older women with systemic hypertension and ventricular hypertrophy. The presence of DD alone predicts worse outcome, with a worsening prognosis as the degree of DD increases. Furthermore, up to 50% of all heart failure patients have a normal ejection fraction ( 0.50) in the absence of major valve disease. Compared with classic systolic heart failure, DD is increasing in incidence and prevalence, triggers at least as many hospitalizations and healthcare expenditures as possible, causes equivalent exercise intolerance, and has a nearly similar death rate, particularly among older patients who are hospitalized. Work to date has suggested that diastolic function may be an additional barometer of cardiovascular risk not only in patients with established symptomatic heart disease but also in patients undergoing major cardiothoracic and vascular surgery. In patient’s undergoing coronary artery bypass graft surgery, Doppler-derived markers of DD were found to be more accurate in predicting cardiac events and mortality than traditional risk scores, including preoperative LV ejection fraction. Preoperative DD, defined by the transmitral peak early filling velocity-to-late diastolic filling velocity (E/A) ratio or transmitral peak early filling velocity-to-early diastolic annular velocity (E/e ) ratio, before cardiac surgery has also been shown to be associated with the need for early inotropic support and increased intensive care unit length of stay. Similarly, reductions in transmitral flow propagation velocity predicts postoperative heart failure and prolonged hospital stay after major vascular surgery. In their eloquent study reported in this journal, Flu et al. included an important and a timely information to the prognostic value of preclinical LV dysfunction in patients undergoing vascular surgery. They examined the independent contribution of (1) asymptomatic isolated DD as defined by conventional Doppler parameters, or (2) asymptomatic systolic dysfunction (defined by LV ejection fraction less than 50% with or without accompanying DD) for predicting 30-day cardiovascular events and longer term mortality in 1,005 consecutive patients, undergoing open vascular or