- Email: [email protected]
Transient constrictive pericarditis: causes and natural history
Results: Increasing age, female gender, use of class 1A antiarrhythmics, diabetes, hypertension and left ventricular mass (among others) were associated with QT prolongation. Over a median follow-up of 11 years there were 1643 deaths (33%), 414 (8% of total) of which were due to coronary disease. Without adjusting for clinical variables, prolongation of QTc was associated with greater mortality in subjects with and without baseline CHD (p⬍0.001), the association being stronger in patients with baseline CHD. After adjusting for clinical variables and cardiac risk factors only those with QTc ⬎450 ms continued to have excess all-cause and CHD mortality. Conclusion: QT prolongation is a marker for increased risk of CHD and total mortality in subjects ⬎65 years of age. Perspective: As discussed in the accompanying editorial there are several limitations to this large population-based study, the most significant of which was the failure to control for left ventricular hypertrophy. Within these limitations one can reasonably assume that significant QTc prolongation (⬎450 ms) may serve as a valuable additional (if not independent) marker for individuals at greater risk of mortality. Whether aggressive treatment strategies aimed at hypertension and coronary disease would lessen this risk remains conjectural. WA
venous limb gangrene, central skin necrosis or both were temporally related to warfarin initiation. Results: At warfarin initiation, five patients had recognized HIT and one had it recognized later. Complications emerged after 2–7 days and consisted of warfarin-induced skin necrosis (n⫽5) and venous limb gangrene (n⫽2); one patient had both. This emerged with unopposed warfarin in four patients and as a direct thrombin inhibitor was being withdrawn in two patients. All had supra-therapeutic international normalized ratios. One patient required leg and breast amputations and another died. Conclusions: The authors concluded that because of the early effects on protein C, warfarin can precipitate venous limb gangrene and/or skin necrosis in the extreme hypercoagulable milieu of HIT. They recommended that with HIT, unopposed warfarin should be avoided and caution is needed during transition from a direct thrombin inhibitor. Warfarin should be initiated at modest doses in patients with HIT after platelet recovery. Perspectives: The study suggests that in the prothrombotic milieu of HIT, alternative anticoagulants other than warfarin should preferably be administered. Most patients will eventually require transition to warfarin for the indication that first mandated anticoagulation, and several precautions could potentially minimize the risks of warfarin initiation in patients with HIT. These include waiting for the platelet count to increase to near normal as the HIT is cooled off, initiating warfarin in modest doses, avoiding an overshoot of the target INR, avoiding unopposed warfarin and assuring adequate levels of an alternative anticoagulant during the transition period. The findings of this study may have broader implications for warfarin use in general. Warfarin can worsen any active thrombotic process and should not be used unopposed initially or in too high a dose with active thrombosis. DM
Transient Constrictive Pericarditis: Causes and Natural History Haley JH, Tajik AJ, Danielson GK, et al. J Am Coll Cardiol 2004; 43:271–5. Study Question: What are causes and natural history of transient constrictive pericarditis (CP)? Methods: Patients who had echocardiographic findings of CP from 1988 through 1999 were identified through review of the Mayo Clinic echocardiogram database had their demographic, clinical and echocardiographic features evaluated. Follow-up echocardiography identified 36 patients in whom constrictive hemodynamics resolved without pericardiectomy. Results: The average age of the patients was 49⫾21 years and 72% were men. The causes for the CP were diverse, the most common being prior cardiovascular surgery (25%). In a subset of 22 patients who were followed serially during the course of their illness, resolution of the constrictive physiologic features occurred at an average of 8.3 weeks after diagnosis. Conclusions: A subset of patients with CP experienced resolution of the disorder without requiring pericardiectomy. Perspective: It is important to recognize that echocardiographic findings of CP resolve without surgery in some patients and perhaps surgical intervention can be avoided in these patients by simply following them expectantly for several months with a repeat follow-up echocardiogram. Unfortunately, most patients with constriction don’t experience spontaneous resolution. RM
The Association Between the Length of the QT Interval and Mortality in the Cardiovascular Health Study Robbins J, Clark Nelson J, Rautaharju PM, Gottdiener JS. Am J Med 2003;24:115:689 –94. Study Question: In a population-based study, to determine if QT prolongation is associated with an adverse clinical outcome. Methods: Corrected (QTc) and uncorrected QT intervals were measured in 5888 subjects ⱖ65 years of age who were part of the Cardiovascular Health Study. Associations between cardiac and all-cause mortality was assessed over a 10-year period and patients further stratified by the presence or absence of coronary heart disease (CHD) at the time of study entry. Subjects were broken into five groups based on QTc ⱕ410 ms, 410 – 420 ms, 420 – 440 ms, 440 – 450 ms and ⬎450 ms.
ACC CURRENT JOURNAL REVIEW Apr 2004
13
venous limb gangrene, central skin necrosis or both were temporally related to warfarin initiation. Results: At warfarin initiation, five patients had recognized HIT and one had it recognized later. Complications emerged after 2–7 days and consisted of warfarin-induced skin necrosis (n⫽5) and venous limb gangrene (n⫽2); one patient had both. This emerged with unopposed warfarin in four patients and as a direct thrombin inhibitor was being withdrawn in two patients. All had supra-therapeutic international normalized ratios. One patient required leg and breast amputations and another died. Conclusions: The authors concluded that because of the early effects on protein C, warfarin can precipitate venous limb gangrene and/or skin necrosis in the extreme hypercoagulable milieu of HIT. They recommended that with HIT, unopposed warfarin should be avoided and caution is needed during transition from a direct thrombin inhibitor. Warfarin should be initiated at modest doses in patients with HIT after platelet recovery. Perspectives: The study suggests that in the prothrombotic milieu of HIT, alternative anticoagulants other than warfarin should preferably be administered. Most patients will eventually require transition to warfarin for the indication that first mandated anticoagulation, and several precautions could potentially minimize the risks of warfarin initiation in patients with HIT. These include waiting for the platelet count to increase to near normal as the HIT is cooled off, initiating warfarin in modest doses, avoiding an overshoot of the target INR, avoiding unopposed warfarin and assuring adequate levels of an alternative anticoagulant during the transition period. The findings of this study may have broader implications for warfarin use in general. Warfarin can worsen any active thrombotic process and should not be used unopposed initially or in too high a dose with active thrombosis. DM
Transient Constrictive Pericarditis: Causes and Natural History Haley JH, Tajik AJ, Danielson GK, et al. J Am Coll Cardiol 2004; 43:271–5. Study Question: What are causes and natural history of transient constrictive pericarditis (CP)? Methods: Patients who had echocardiographic findings of CP from 1988 through 1999 were identified through review of the Mayo Clinic echocardiogram database had their demographic, clinical and echocardiographic features evaluated. Follow-up echocardiography identified 36 patients in whom constrictive hemodynamics resolved without pericardiectomy. Results: The average age of the patients was 49⫾21 years and 72% were men. The causes for the CP were diverse, the most common being prior cardiovascular surgery (25%). In a subset of 22 patients who were followed serially during the course of their illness, resolution of the constrictive physiologic features occurred at an average of 8.3 weeks after diagnosis. Conclusions: A subset of patients with CP experienced resolution of the disorder without requiring pericardiectomy. Perspective: It is important to recognize that echocardiographic findings of CP resolve without surgery in some patients and perhaps surgical intervention can be avoided in these patients by simply following them expectantly for several months with a repeat follow-up echocardiogram. Unfortunately, most patients with constriction don’t experience spontaneous resolution. RM
The Association Between the Length of the QT Interval and Mortality in the Cardiovascular Health Study Robbins J, Clark Nelson J, Rautaharju PM, Gottdiener JS. Am J Med 2003;24:115:689 –94. Study Question: In a population-based study, to determine if QT prolongation is associated with an adverse clinical outcome. Methods: Corrected (QTc) and uncorrected QT intervals were measured in 5888 subjects ⱖ65 years of age who were part of the Cardiovascular Health Study. Associations between cardiac and all-cause mortality was assessed over a 10-year period and patients further stratified by the presence or absence of coronary heart disease (CHD) at the time of study entry. Subjects were broken into five groups based on QTc ⱕ410 ms, 410 – 420 ms, 420 – 440 ms, 440 – 450 ms and ⬎450 ms.
ACC CURRENT JOURNAL REVIEW Apr 2004
13