Chin Med J (Taipei) 1998;61:S99.

Hemodynamic Assessment for Managing Congestive Heart Failure: What Do We Need to Know?

David A. Kass, M.D.

The Johns Hopkins Medical Institutions, Baltimore, MD. USA

Abstract

Although patients with the clinical syndrome of heart failure share common symptoms of exertional dyspnea, fatigue, and fluid accumulation, the underlying cardiovascular disturbances that generate them can vary considerably. For example, nearly half of elderly patients with heart failure symptoms have preserved systolic function, and are presumed to have abnormalities related to diastole and abnormal vascular loading. As the therapeutic armamentarium expands, it is becoming more important to define these differences in pathophysiology among individual patients, so as to apply the most effective optimal therapy.

The major goals of hemodynamic evaluation are: 1) identification of the primary cardiac abnormality (i.e. systolic, diastolic, adverse loading, pericardial constraint); 2) characterization of basal venous and arterial loading and their interaction with the heart; and 3) assessment of integrated cardiovascular reserve. Echo-Doppler assessment provides invaluable primary screening for identifying the presence of systolic failure, and suggesting diastolic abnormalities. Most of these assessments, however, do not incorporate pressure information. This is an important limitation, since most cardiac-specific function analysis requires knowledge both of the motion of the heart and the pressure loads that exist at the same time. Combining these variables enables calculation of parameters such as cardiac heart load, contractile and work performance, cardiac power output, and pump efficiency. Pressure data are often provided by invasive catheterization studies, but this information is likewise rarely combined with ventriculographic or other imaging data.

More precise and detailed analysis of the hemodynamics in heart failure patients is achievable by combining pressure with volume/flow data, and methods are available by which this is done invasively and non-invasively. Examples are ventricular power assessment which can be obtained non-invasively, pressurevolume relation analysis, which may be assessed by invasive methodologies, and by newer approaches using non-invasive data only. The latter is particularly valuable, in that one may obtain insight into the interaction of the ventricle with the arterial system - and thus predict likely benefits to be derived from vasodilator therapy, inotropic interventions, or changes in venous loading. Failing hearts - even those with similarly reduced ejection fractions, can behave quite differently with respect to the relative change in cardiac output versus systolic pressure for the same afterload or preload reduction intervention. The capacity to determine what type of heart a given patient has in this regard can greatly help target the effective titration of load reduction - a major target of heart failure treatment. Furthermore, non-invasive approaches are amenable to longitudinal evaluation.

Recent studies have suggest that careful assessment and therapeutic targeting of cardiac hemodynamisc, particularyly those based on right heart catheterization pressures, may be useful in minimizing hospitalization costs and need for transplantation in heart failure patients. With the evolution of more sophisticated and fully non-invasive approaches for cardiovascular evaluation, we can start to evaluate if more comprehensive analysis will prove even more useful for identifying the appropriateness and adequacy of therapy and nature of the underlying cardiac abnormality.

[Chin Med J (Taipei) 1998;61:S99.]