Interferon-induced coronary vasospasm. A case history

Endothelial dysfunction and decreased exercise tolerance in interferon-alpha therapy in chronic hepatitis C: relation between exercise hyperemia and endothelial function

BACKGROUND

We previously reported that reversible endothelial dysfunction is caused by interferon-alpha therapy (IFN) in patients with chronic hepatitis C. In experimental studies, limb blood flow during exercise is reported to be dependent on endothelium-derived nitric oxide.

HYPOTHESIS

The purpose of this study was to confirm the effect of IFN on endothelial function and to investigate whether exercise hyperemia is dependent on endothelial function in humans.

METHODS

We performed symptom-limited exercise treadmill testing and measured flow-mediated vasodilation (FMD, endothelium-dependent vasodilation) and sublingual glyceryl-trinitrate-induced dilation (GTN-D, 0.3 mg, endothelium-independent vasodilation) in the brachial artery by using high-resolution ultrasound in 10 patients with chronic active hepatitis C (age 53 +/- 11 years, 2 men, 8 women) before and immediately after administration of recombinant interferon 2b (10 million U/day) for 4 weeks.

RESULTS

There were no significant abnormal findings in any patients in routine studies of 24-h ambulatory electrocardiogram monitoring, two-dimensional echocardiography, and exercise treadmill testing both before and after treatment. Leg fatigue and exhaustion were the reasons for termination of exercise treadmill testing in each patient. Pressure rate product was calculated at rest and peak exercise. Interferon-alpha therapy significantly (p<0.05) decreased FMD (6.8 +/- 3.1 vs. 1.9 +/- 2.6%), exercise treadmill testing tolerance time (437 +/- 89 vs. 395 +/- 62 s) and peak pressure rate product (283 +/- 41 vs. 241 +/- 47 mmHg x beats/min x 10(-2)), but not GTN-D (13.4 +/- 5.4 vs. 17.0 +/- 5.5%). The change of FMD due to IFN significantly and highly correlated with exercise treadmill testing tolerance time (r = 0.86, p<0.001), but not with change of peak pressure rate product, suggesting that FMD is more closely related to the condition of the peripheral circulation than is cardiac performance.

CONCLUSION

These results suggest that IFN in patients with chronic hepatitis C impairs endothelial function and exercise tolerance, and that endothelial function might be at least partly involved in exercise hyperemia in humans.

Ischemic colitis during pegylated interferon-alpha and ribavirin therapy for chronic hepatitis C

Rare cases of ischemic colitis associated with interferon-alpha (IFN-alpha) treatment for chronic hepatitis C (HCV) infection and metastatic cancer have been reported. The present study describes the first case of ischemic colitis attributable to pegylated IFN-alpha and ribavirin combination therapy in an HCV-infected patient after 34 weeks of treatment. The clinical presentation, endoscopic appearance and histopathology of the colon were consistent with ischemic colitis, and the patient's symptoms rapidly resolved with cessation of therapy. The association between the therapy and the pathogenesis of ischemic colitis is unclear, but immunoregulatory, vasospastic and procoagulant mechanisms have been proposed. Physicians should be aware of this complication, and should consider it in any HCV-infected patient taking pegylated IFN-alpha and ribavirin who develops abdominal discomfort and gastrointestinal bleeding.

Recombinant interferon alpha treatment decreases heart rate variability indices and impairs exercise tolerance in patients with chronic hepatitis

Complications of interferon (IFN) therapy include cardiac arrhythmias, impaired cardiac function and myocardial ischemia. Decreased heart rate variability (HRV) indices, impaired exercise tolerance and decreased left ventricular (LV) function are related to unfavorable outcome of heart disease. To investigate the effect of IFN therapy on HRV, exercise tolerance and cardiac function, 24-h ambulatory electrocardiographic monitoring (AECG), two-dimensional echocardiography, and exercise treadmill testing (ETT) was performed in 9 patients (age 56 +/- 9 years-old) with chronic hepatitis and without underlying heart disease before and after treatment with IFN (recombinant alpha 2b; 10 x 10(6) U/day for 4 weeks). HRV parameters consisted of standard deviation of RR interval (sdNN, ms), SDANN (ms), S.D. index (ms), rMSSD (ms), pNN50 (%) and frequency analysis of heart rate spectrum resulted in low (ms, 0.04-0.15 Hz), high (ms, 0.15-0.40 Hz) and total (ms, 0.01-1.00 Hz) frequency components. Ischemia was not detected by AECG or ETT, and LV function was normal after INF treatment in all patients. However, INF treatment resulted in a decrease in exercise tolerance time (449 +/- 94 s vs. 329 +/- 67 s, P < 0.05) and a decrease in several HRV parameters (S.D. index, 42 +/- 5 ms vs. 37 +/- 9 ms; rMSSD, 22 +/- 5 ms vs. 19 +/- 4 ms; pNN50, 4 +/- 3% vs. 2 +/- 1%; P < 0.05). Further, patients treated with INF tended to have a lower sdNN and total frequency spectra, although this difference did not reach the level of statistical significance. These data suggest that the arrhythmogenic effect of INF may be mediated by decreases in HRV and impairment of exercise tolerance even in patients without overt heart diseases. Further, INF therapy may be contraindicated in patients with predisposing severe cardiac disorders, including arrhythmias, ischemia and decreased LV function.

Interferon-induced Raynaud's syndrome

OBJECTIVE

To review the clinical features, diagnosis, treatment, and outcome of interferon-induced Raynaud's phenomenon.

METHODS

The medical literature was reviewed from 1967 to November 2001 with the assistance of a MEDLINE search using the key words: Raynaud, Interferon, ischemia, thrombosis and necrosis. A qualitative review was performed after the articles were abstracted and the relevant information was summarized.

RESULTS

Twenty-four cases of interferon-induced Raynaud's phenomenon (including our patient) are described. Interpheron-alpha was the most common causative agent (14 cases). The symptoms appeared weeks to years after beginning treatment and varied from mild vasospasm to occlusion of digital arteries and tissue necrosis (14 cases), sometimes necessitating finger amputation (6 patients). Digital plethysmography, arteriography and capillaroscopy were valuable diagnostic tools. In 4 cases, cardiac, ophthalmic, or central nervous system drug-induced ischemia accompanied the peripheral Raynaud's phenomenon. Of the 15 cases with a documented outcome, withdrawal of the drug alone resulted in complete (6 patients) or partial (1 patient) recovery. In the others, supportive therapy was needed. The recovery period lasted from 2 weeks to 3 months. In 2 patients, continuation of treatment was possible.

CONCLUSIONS

Raynaud's phenomenon and related complications must be recognized as possible side effects of interferon therapy. Early diagnosis and withdrawal of the drug may prevent unnecessary morbidity and disability.

Interferon-alpha induced Raynaud's syndrome

The cytokine interferon-alpha (IFN-alpha) is increasingly prescribed for a number of indications, especially viral hepatitis and several malignancies. Two patients are described who developed Raynaud's syndrome during treatment with IFN-alpha as adjuvant therapy for high-risk melanoma. With a review of the available literature the symptomatology, possible pathophysiologic mechanisms and treatment options are discussed.

[Coronary spasm--a clinically relevant problem?]

Coronary spasms are defined as reversible coronary stenosis, which limits coronary blood flow under resting conditions. The demonstration of either spontaneous or provoked coronary spasm proves coronary hypercontractility and thus the diagnosis of variant angina. Several stimuli can provoke coronary vasospasm, but the highest sensitivity and specificity has been shown with ergonovine. Alternatively acetylcholine or with less sensitivity, but high specificity, hyperventilation may be employed. Typically coronary vasospasm presents with angina pectoris at rest; the manifestation with myocardial infarction or syncope are of great clinical importance. The prevalence of the disease is unknown due to the rarely performed provocation tests in Western countries. The incidence of positive test results strongly depends on the symptoms of the patients; from 0% in patients without any evidence for myocardial ischemia up to 54% in patients with typical angina at rest have been observed. Coronary vasospasm is closely related to atherosclerotic coronary artery disease, since intravascular ultrasound studies reveal atherosclerotic plaques in almost any spastic segment. Risk factors for coronary artery disease and coronary vasospasm, however, differ profoundly. For the latter cigarette smoking is the only established risk factor. Although several candidates and predisposing factors (serotonin, histamine, thromboxane, endothelin) have been described, the mediators and the pathogenesis of the disease remains unknown. Endothelial dysfunction alone is not sufficient to explain the features of variant angina. Some evidence supports the hypothesis of local inflammation. The mortality in variant angina depends on the extent of the coronary artery disease. Pure coronary vasospasm does not lead to increased mortality; patients with highly active disease presenting with syncope may have an increased risk. Medical treatment should include long-acting calcium antagonists or nitrates, beta-blockers may even favor the occurrence of ischemic attacks. Although the benefit has not been proven, the use of aspirin may considered in highly active disease.