A prognostic index relating 24-hour ambulatory blood pressure to cardiac events in ischemic cardiomyopathy following defibrillator implantation

BACKGROUND

We assessed the role of left ventricular ejection fraction and of ambulatory blood pressure monitoring (ABPM) to predict cardiac death and heart failure in patients with defibrillator fulfilling MADIT II criteria. ABPM variables assessed included: mean 24 hours diastolic and systolic blood pressure, mean 24 hours heart rate, and pulse pressure.

METHODS

We studied 105 consecutive patients (age 67 +/- 11), all with a defibrillator and ejection fraction <or= 30%).

RESULTS

At 1-year follow-up, there were 29 events (25%), three cardiac deaths, and 26 hospitalizations for heart failure. Age, creatinine, mean 24 hours diastolic blood pressure, and mean 24 hours systolic blood pressure (but not ejection fraction) were associated with events. A prognostic index (PI) was built by age and ABPM variables, according to the formula (120--age) + (mean 24 hours diastolic blood pressure + mean 24 hours systolic blood pressure). Receiver operating characteristic curves showed the best cutoff for PI = 220 (sensitivity 81%, specificity 71%, positive predictive value 56%, negative predictive value 88%). Cox regression analysis confirmed the significant association between lower PI (< 220) and clinical events (HR 4.8, 95% CI 1.8-12.3, P = 0.0001 for PI). Overall, 12% of patients with high PI values (>or= 220 n = 71) had clinical events at 12-month follow-up, compared with 61% of patients with low PI (< 220 n = 34) (P < 0.0001).

CONCLUSION

The PI built by mean 24 hours diastolic and systolic blood pressure and age could be a simple method to stratify risk of cardiac death and acute heart failure in MADIT II patients, in whom ejection fraction, uniformly depressed, is not predictive.

Ambulatory blood pressure monitoring early after acute myocardial infarction: development of a new prognostic index

OBJECTIVES

The aim of our study was to assess the possible role of a prognostic index based on ambulatory blood pressure monitoring in a large cohort of patients with recent myocardial infarction.

METHODS

The study population included 1335 consecutive patients admitted for ST elevation myocardial infarction and discharged alive from 48 Italian hospitals participating in the multicentric IMPRESSIVE (Infarto Miocardico, Pressione arteriosa e frequenza cardiaca. Studio Italiano di Valutazione Epidemiologica) study. Ambulatory blood pressure monitoring was performed 3 weeks after discharge, with a clinical follow-up of 12 months. End-points included cardiac death and new admission for heart failure. A prognostic index was obtained from the ambulatory blood pressure monitoring variables according to the formula: (220-age)-mean 24 h heart rate (m24hHR)+mean 24 h diastolic blood pressure (m24hDBP).

RESULTS

Among many potential predictors only left-ventricular ejection fraction, creatinine levels, Killip class and the prognostic index were independently associated with events during the follow-up. In particular, higher values of the prognostic index were associated with a lower incidence of events, with an odds ratio of 0.958 (95% confidence intervals 0.943-0.974) and a 4% reduction in risk for each point of the prognostic index. Overall incidence of cardiac events was 6-fold higher in patients within the lowest quartile of the prognostic index (< or =148) compared with the other three quartiles (12 vs. 2, 1.4 and 2% respectively in the other three quartiles; P<0.0001).

CONCLUSIONS

A simple prognostic index based on ambulatory blood pressure monitoring and age may be a useful tool in predicting cardiac death and heart failure in patients with recent myocardial infarction.