Functional and anatomic correlates of markedly abnormal stress tests

Prior research has shown that ischemic stress tests can indicate coronary disease severity. However, the relationship between test results and patient symptoms remains unclear. This gap motivated a closer look at asymptomatic patients with abnormal stress tests. Established knowledge includes the Bruce protocol for stress testing and its use in diagnosing ischemia. No prior work had resolved how anatomical findings align with functional outcomes. This paper's contribution is examining patients with marked ST depression regardless of symptoms. The study adds clarity on whether asymptomatic patients with abnormal tests have significant coronary disease. It challenges assumptions that symptoms alone predict disease severity.

The aim was to evaluate functional and anatomical correlations in patients with markedly abnormal stress tests. Researchers sought to determine if asymptomatic patients with severe ST depression have significant coronary disease. The specific problem was understanding how test results relate to anatomical findings and symptoms. Motivation came from the need to improve diagnostic accuracy beyond symptom-based assessments. The study focused on patients with over 2 mm ST depression during exercise. It aimed to compare asymptomatic patients with those having type I and II angina. The goal was to identify whether anatomical severity correlates with functional status. This could refine how clinicians interpret stress test results in asymptomatic individuals.

The study involved 120 patients with markedly positive ischemic stress tests. Participants were divided into three groups based on angina type or absence. All underwent exercise stress testing using the Bruce protocol. Cardiac catheterization occurred within two months of testing. Exercise variables included time of ischemia onset, heart rate, and rate-pressure product. Coronary anatomy was assessed via arteriograms and scoring systems. Groups were compared for differences in coronary disease extent and collateral circulation. Statistical analysis focused on identifying correlations between exercise responses and anatomical findings.

No significant differences were found in exercise variables across the three groups. Asymptomatic patients (group A) had similar ischemic responses to those with angina. Two asymptomatic patients had normal coronary arteriograms. The remaining asymptomatic patients showed no anatomical differences from symptomatic groups. Collateral vessels in jeopardy were 18% in group A versus 52% in groups B and C. Triple vessel disease was present in 57% of the total group. Left main coronary artery disease occurred in 16% of patients. The only useful exercise variable for predicting severe disease was abnormal blood pressure response.

The authors suggest that marked ST depression on stress tests identifies severe coronary disease regardless of symptoms. Asymptomatic patients with abnormal tests may still have significant anatomical findings. The study implies that functional status does not always reflect anatomical severity. The researchers propose that abnormal blood pressure response is a key indicator of disease severity. They note that collateral vessel jeopardy differs significantly between groups. The findings suggest that stress test interpretation should not rely solely on symptoms. The authors state that anatomical severity can exist independently of functional status. These results may influence diagnostic approaches for asymptomatic patients with abnormal stress tests.