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Effect of cold stress on coronary sinus blood flow in patients with scleroderma
H T Colfer1, S K Das, L Dabich
1Department of Internal Medicine, University of Michigan, Ann Arbor.
Insights
Scleroderma heart disease may involve myocardial damage, but this study found no abnormal coronary blood flow response to the cold pressor test in patients with scleroderma.
Area of Science:
- Cardiology
- Rheumatology
- Pathophysiology
Background:
- Scleroderma can cause myocardial damage, but the underlying mechanism remains unclear.
- Histologic studies show myocardial damage in scleroderma patients, suggesting potential coronary blood flow issues.
- Previous studies hypothesized reduced coronary blood flow due to abnormal vasomotor tone in scleroderma heart disease.
Purpose of the Study:
- To investigate coronary blood flow response to cold pressor test in scleroderma patients.
- To determine if scleroderma is associated with abnormal coronary vasomotor tone or reduced blood flow.
- To compare coronary blood flow in scleroderma patients versus healthy controls.
Main Methods:
- Cardiac catheterization with thermodilution method to measure coronary sinus blood flow.
- Inclusion of 5 scleroderma patients and 5 healthy controls with normal coronary angiograms.
- Performance of a cold pressor test (hand immersion in ice water) during measurements.
Main Results:
- Baseline coronary blood flow was not significantly different between scleroderma patients and controls.
- The cold pressor test induced only a small, insignificant increase in coronary blood flow in both groups.
- No absolute reduction in coronary blood flow was observed in scleroderma patients during the test.
Conclusions:
- The cold pressor test does not appear to cause abnormal coronary vasomotor tone or reduced coronary blood flow in scleroderma patients.
- Findings challenge previous hypotheses suggesting abnormal coronary blood flow response in scleroderma heart disease.
- Further research is needed to elucidate the exact mechanisms of cardiac involvement in scleroderma.
Abstract:
The mechanism of cardiac involvement in scleroderma is not known. Histologic studies of the myocardium in patients who died of scleroderma revealed that half had myocardial damage. Characteristic involvement ranges from focal contraction-band necrosis to diffuse fibrosis despite the absence of obstructive coronary artery disease of the major epicardial vessels. These findings suggest that scleroderma heart disease might result from episodic reduction of coronary blood flow due to abnormalities of coronary vasomotor tone. Studies using cold pressor thallium 201 myocardial perfusion scans support this hypothesis. Our study measured coronary blood flow during hand immersion in ice water at cardiac catheterization to determine whether patients with scleroderma had an abnormal coronary blood flow response. Coronary sinus blood flow was measured using a thermodilution method. Five patients with scleroderma were compared with 5 control subjects. All patients and controls had normal coronary angiograms. The coronary blood flow at baseline in the scleroderma and the control group (130 +/- 33 mL/min and 86 +/- 27 mL/min, respectively) was not significantly different. During the cold pressor test, both groups had a small, insignificant increase in coronary blood flow from baseline to 60 seconds (130 to 144 mL/min, scleroderma patients; 86 to 89 mL/min, control subjects). Our findings suggest that the cold pressor test does not cause an abnormal increase in coronary vasomotor tone or an absolute reduction in coronary blood flow in patients with scleroderma, as previously suggested by thallium 201 cold pressor studies.