- Email: [email protected]
Postmenopausal estrogen and progestin use and the risk of cardiovascular disease
IN
CONSULTATION
any significant effect in heart transplant recipients heart denervation suggests a neural reflex.
with
sis of acute mesenteric ischemia. Materials and Methods: Reviewers blinded to patient diagnoses retrospectively compared the CT scans in a study group with those in a control group. The study group comprised 39 consecutive patients (23 men, 16 women; aged 55-88 years) with surgically proved acute mesenteric ischemia. The control group comprised 24 patients (13 men, 11 women; aged 50-82 years) with suspected acute mesenteric ischemia that was disproved at surgery Results: For the diagnosisof acute mesenteric ischemia,eachof the following findings had a specificity of more than 95% and a sensitivity of lessthan 30%: arterial or venous thrombosis,intramural gas,portal venous gas, focal lack of bowel-wall enhancement, and liver or splenic infarcts. When CT was used in the diagnosis of suspectedacute mesenteric ischemia, the detection of at leastone of thesesignsresulted in a sensitivity of 64% (25 of 39; confidence interval, 0.49,0.79), a specificity of 92% (22 of 24; confidence interval, 0.81, l.OO), and an accuracy of 75% (47 of 63; confidence interval, 0.64,0.86). Conclusion: Dynamic, contrast-enhanced CT is a valuable tool in the diagnosis of and determination of prognosis in acute mesenteric ischemia.
An Analysis of the Lowest Effective Intensity of Prophylactic Anticoagulation for Patients With Nonrheumatic Atrial Fibrillation Elaine M. Hyiek, Steven J. Skates, Mary A Sheehan, Daniel E. Singer. Medical Practices Evaluation Center, Massachusetts General Hospital, Boston, MA. N Engl
] Med1996;335:540-6. Background: To avert major hemorrhage, physicians need to know the lowest intensity of anticoagulation that is effective in preventing stroke in patients with atria1 fibrillation. Since the low rate of stroke has made it difficult to perform prospective studies to resolve this issue, we conducted a case-control study. Methods: We studied 74 consecutive patients with atria1 fibrillation who were admitted to our hospital from 1989 through 1994 after having an ischemic stroke while taking warfarin. For each patient with stroke, three controls with nonrheumatic atria1 fibrillation who were treated as outpatients were randomly selected from the 1994 registry of the anticoagulant-therapy unit (222 controls). We used the international normalized ratio (INR) to measure the intensity of anticoagulation. For the patients with stroke, we used the INR at admission; for the controls, we selected the INR that was measured closest to the month and day of the matched case patient’s hospital admission. Results: The risk of stroke rose steeply at INRs below 2.0. At an INR of 1.7, the adjusted odds ratio for stroke, as compared with the risk at an INR of 2.0, was 2.0 (95 percent confidence interval, 1.6 to 2.4); at an INR of 1.5, it was 3.3 (95 percent confidence interval, 2.4 to 4.6); and at an INRof 1.3, it was 6.0 (95 percent confidence interval, 3.6 to 9.8). Other independent risk factors were previous stroke (odds ratio, 10.4; 95 percent confidence interval, 4.4 to 24.5), diabetes mellitus (odds ratio, 2.9; 95 percent confidence interval, 1.3 to 6.5), hypertension (odds ratio, 2.5; 95 percent confidence interval, 1.1 to 5.7), and current smoking (odds ratio, 5.7; 95 percent confidence interval, 1.4 to 24.0). Conclusions: Among patients with atria1 fibrillation, anticoagulant prophylaxis is effective at INRs of 2.0 or greater. Since previous studies have indicated that the risk of hemorrhage rises rapidly at INRs greater than 4.0 to 5.0, tight control of anticoagulant therapy to maintain the INR between 2.0 and 3.0 is a better strategy than targeting lower, less effective levels of anticoagulation. Acute Mesenteric Contrast-Enhanced
Ischemia: CT
Diagnosis
Postmenopausal Estrogen and Progestin Use and the Risk of Cardiovascular Disease Francine Grodstein, Meir j. Stampfer, JoAnn E. Manson, Graham A Colditz, Walter C Willett, Bernard Rosner, Frank E. Speizer, Charies H. Hennekens. Grodstein at the Channing laboratory, Boston, MA. N Engl J Med 199633545~-61.
Background:Estrogen therapy in postmenopausalwomen has been associatedwith a decreasedrisk of heart disease. There is little information, however, about the effect of combined estrogen and progestin therapy on the risk of cardiovascular disease.Methods:We examined the relation between cardiovascular diseaseand postmenopausalhormone therapy during up to 16 years of follow-up in 59,337 women from the Nurses’Health Study, who were 30 to 55 years of ageat baseline. Information on hormone use was ascertained with biennial questionnaires. From 1976 to 1992, we documented 770 casesof myocardial infarction or death from coronary diseasein this group and 572 strokes. Proportional-hazards modelswere usedto calculate relative risks and 95 percent confidence intervals, adjusted for confounding variables.Results:We observed a marked decrease in the risk of major coronary heart diseaseamong women who took estrogenwith progestin, ascomparedwith the risk among women who did not use hormones (multivariate adjusted relative risk, 0.39; 95 percent confidence interval, 0.19 to 0.78) or estrogen alone (relative risk, 0.60; 95 percent confidence interval, 0.43 to 0.83). However, there was no significant associationbetween stroke and use of combined hormones (multivariate adjusted relative risk, 1.OQ;95 percent confidence interval, 0.66 to 1.80) or estro-
With
P.G. Taourel, M. Deneuville, JA Pradel, D. Regent, ].M. Bruel. Department of Medical Imaging, Hopital Saint-Eloi, Montpellier, France. Radiology I996;199:632-6.
Purpose: To evaluate the accuracy of dynamic, contrast material-enhanced computed tomography (CT) in the diagnoACC CURRENT
JOURNAL
REVIEW
87
MaddApnll997
IN
CONSULTATION
gen alone (relative risk, 1.27; 95 percent confidence interval, 0.95 to 1.69). Conclusions: The addition of progestin does not appear to attenuate the cardioprotective effects of postmenopausal estrogen therapy. Low Energy Internal Fibrillation Resistant
tricular premature contractions (VPCs), 556 + 1415. VPCs were multifocal in 9%, in runs in 25%, and early in 1%. In 29 (40%) of recordings, VPCs appeared mainly during and for several hours after HD. ST-T changes were seen in 43 (60%). In 11, ST depression occurred during and a few hours after HD. Patients receiving HD showed diverse ECG abnormalities. Holter ECGs revealed a high incidence of arrhythmias and ST-T changes, which frequently appeared in relation to HD timing.
Cardioversion of Atrial to Transthoracic Shocks
5. Hark Sopher, Francis D. Murgatroyd, Alistair K.B. Slade, Ivan Blankoff, Edward Rowland, David E. Ward, A. John Camm. St George’s Hospital and Medical School, Cranmer Terrace, London, Great Britain. Heart 1996;75:635-8.
Objective: To investigate the efficacy of internal cardioversion using low energy shocks delivered with a biatrial electrode configuration in chronic atria1 fibrillation resistant to transthoracic shocks. Methods: Low energy internal cardioversion was attempted in 11 patients who had been in atria1 fibrillation for 233 (SD 193) days and had failed to cardiovert with transthoracic shocks of 360 J in both apex-base and anteriorposterior positions. Synchronised biphasic shocks of up to 400 V (a6 J) were delivered, usually with intravenous sedation only, between high surface area electrodes in the right atrium and the left atrium (coronary sinus in nine, left pulmonary artery in one, left atrium via patent foramen ovale in one). Results: Sinus rhythm was restored in 8/11 patients. The mean leading edge voltage of successful shocks was 363 (46) V [4.9 (1.2) J]. Higher energy shocks induced transient bradycardia [time to first R wave 1955 (218) msl. No proarrhythmia or other acute complications were observed. Conclusions: Low energy internal cardioversion of atria1 fibrillation can restore sinus rhythm in patients in whom conventional transthoracic shocks have failed. Electrocardiographic Abnormalities Receiving Hemodialysis
Occult Ascending of an Air Bag
Aortic
Rupture
in the Presence
].A. Dunn, M.G. Williams. James H. Quillen College of Medicine, East Tennessee State Uniiersi~, Johnson City, TN. Ann Thorac Surg 1996621577-t.
A patient presented to the emergency department after a high-speed decelerating-type motor vehicle accident, Due to activation of his air bag device, the patient was without significant obvious injury. Upon evaluation in the emergency department he was also without any radiographic or physical signs of serious injury. In the ensuing 24 hours, severe chest pain developed, and subsequent aortography demonstrated a tear of his ascending aorta just distal to the root. Although occult injury to the aorta and great vessels does occur in a small percentage of patients, it is quite rare. However, with the advent of air bags, in the absence of associated injuries, signs, and symptoms, a high index of suspicion must be entertained in decelerating-type accidents to diagnose occult injury to the aorta and great vessels.
in Patients Long-Term Use of Nicotine Gum Is Associated With Hyperinsulinemia and Insulin Resistance
5. Abe, M. Yoshizawa, N. Nakanishi, T. Yazawa, K. Yokota, M. Honda, G. Sloman. Department of Internal Medicine, Keio Uniiersity, Tokyo, Japan. 1996;13 I:I 137-44.
B. Eliasson, M-R Taskinen, U. Smith. Lundberg lab. for Diabetes Research, Department of Internal Medicine, Sahlgrenska Universiq Hospital, Goteborg, Sweden. 1996;94:878-81.
We assessed standard 12-lead and Holter electrocardiographic (ECG) abnormalities in maintenance hemodialysis (HD) patients, Of 221 outpatients receiving HD, 143 (65%) had ECG abnormalities. Rates were higher in male, elderly, hypertensive, and diabetic patients than in female, younger, normotensive, and nondiabetic patients. The prevalence of ECG changes correlated inversely with HD duration. Serial ECGs were compared in 87 patients whose average HD duration was 7.5 5 2.5 years. Thirty-four patients (39%) showed normal ECGs throughout, 27 (31%) relatively stable abnormalities, 22 (25%) worsening, and 4 (5%) reversion to normal. Age, hypertension, and diabetes are factors related to abnormal ECG findings. Among the 142 Holter recordings from 72 patients, 70 (97%) were basically in sinus rhythm, and 2 (3%) were in atria1 fibrillation. The average frequency of supraventricular premature contractions (SVPCs) was 1597 ? 9725 per 24 hours, and that of venACC CURRENT
JOURNAL
Background: Insulin sensitivity and cardiovascular risk profile were examined in 20 healthy, nonobese, middle-aged men who were long-term users of nicotine-containing chewing gum and in 20 matched control subjects who did not use nicotine. Methods and Results: Long-term use of nicotinecontaining chewing gum was associated with insulin resistance and hyperinsulinemia. The degree of insulin sensitivity correlated negatively to the extent of nicotine use measured as plasma cotinine levels. Conclusions: These findings suggest that nicotine is the major constituent in cigarette smoke that leads to insulin resistance, metabolic abnormalities associated with the insulin resistance syndrome, and increased cardiovascular morbidity. Thus, the use of nicotine replacement therapy during smoking cessation should be transient and limited. REVIEW
88
March/April
1997
CONSULTATION
any significant effect in heart transplant recipients heart denervation suggests a neural reflex.
with
sis of acute mesenteric ischemia. Materials and Methods: Reviewers blinded to patient diagnoses retrospectively compared the CT scans in a study group with those in a control group. The study group comprised 39 consecutive patients (23 men, 16 women; aged 55-88 years) with surgically proved acute mesenteric ischemia. The control group comprised 24 patients (13 men, 11 women; aged 50-82 years) with suspected acute mesenteric ischemia that was disproved at surgery Results: For the diagnosisof acute mesenteric ischemia,eachof the following findings had a specificity of more than 95% and a sensitivity of lessthan 30%: arterial or venous thrombosis,intramural gas,portal venous gas, focal lack of bowel-wall enhancement, and liver or splenic infarcts. When CT was used in the diagnosis of suspectedacute mesenteric ischemia, the detection of at leastone of thesesignsresulted in a sensitivity of 64% (25 of 39; confidence interval, 0.49,0.79), a specificity of 92% (22 of 24; confidence interval, 0.81, l.OO), and an accuracy of 75% (47 of 63; confidence interval, 0.64,0.86). Conclusion: Dynamic, contrast-enhanced CT is a valuable tool in the diagnosis of and determination of prognosis in acute mesenteric ischemia.
An Analysis of the Lowest Effective Intensity of Prophylactic Anticoagulation for Patients With Nonrheumatic Atrial Fibrillation Elaine M. Hyiek, Steven J. Skates, Mary A Sheehan, Daniel E. Singer. Medical Practices Evaluation Center, Massachusetts General Hospital, Boston, MA. N Engl
] Med1996;335:540-6. Background: To avert major hemorrhage, physicians need to know the lowest intensity of anticoagulation that is effective in preventing stroke in patients with atria1 fibrillation. Since the low rate of stroke has made it difficult to perform prospective studies to resolve this issue, we conducted a case-control study. Methods: We studied 74 consecutive patients with atria1 fibrillation who were admitted to our hospital from 1989 through 1994 after having an ischemic stroke while taking warfarin. For each patient with stroke, three controls with nonrheumatic atria1 fibrillation who were treated as outpatients were randomly selected from the 1994 registry of the anticoagulant-therapy unit (222 controls). We used the international normalized ratio (INR) to measure the intensity of anticoagulation. For the patients with stroke, we used the INR at admission; for the controls, we selected the INR that was measured closest to the month and day of the matched case patient’s hospital admission. Results: The risk of stroke rose steeply at INRs below 2.0. At an INR of 1.7, the adjusted odds ratio for stroke, as compared with the risk at an INR of 2.0, was 2.0 (95 percent confidence interval, 1.6 to 2.4); at an INR of 1.5, it was 3.3 (95 percent confidence interval, 2.4 to 4.6); and at an INRof 1.3, it was 6.0 (95 percent confidence interval, 3.6 to 9.8). Other independent risk factors were previous stroke (odds ratio, 10.4; 95 percent confidence interval, 4.4 to 24.5), diabetes mellitus (odds ratio, 2.9; 95 percent confidence interval, 1.3 to 6.5), hypertension (odds ratio, 2.5; 95 percent confidence interval, 1.1 to 5.7), and current smoking (odds ratio, 5.7; 95 percent confidence interval, 1.4 to 24.0). Conclusions: Among patients with atria1 fibrillation, anticoagulant prophylaxis is effective at INRs of 2.0 or greater. Since previous studies have indicated that the risk of hemorrhage rises rapidly at INRs greater than 4.0 to 5.0, tight control of anticoagulant therapy to maintain the INR between 2.0 and 3.0 is a better strategy than targeting lower, less effective levels of anticoagulation. Acute Mesenteric Contrast-Enhanced
Ischemia: CT
Diagnosis
Postmenopausal Estrogen and Progestin Use and the Risk of Cardiovascular Disease Francine Grodstein, Meir j. Stampfer, JoAnn E. Manson, Graham A Colditz, Walter C Willett, Bernard Rosner, Frank E. Speizer, Charies H. Hennekens. Grodstein at the Channing laboratory, Boston, MA. N Engl J Med 199633545~-61.
Background:Estrogen therapy in postmenopausalwomen has been associatedwith a decreasedrisk of heart disease. There is little information, however, about the effect of combined estrogen and progestin therapy on the risk of cardiovascular disease.Methods:We examined the relation between cardiovascular diseaseand postmenopausalhormone therapy during up to 16 years of follow-up in 59,337 women from the Nurses’Health Study, who were 30 to 55 years of ageat baseline. Information on hormone use was ascertained with biennial questionnaires. From 1976 to 1992, we documented 770 casesof myocardial infarction or death from coronary diseasein this group and 572 strokes. Proportional-hazards modelswere usedto calculate relative risks and 95 percent confidence intervals, adjusted for confounding variables.Results:We observed a marked decrease in the risk of major coronary heart diseaseamong women who took estrogenwith progestin, ascomparedwith the risk among women who did not use hormones (multivariate adjusted relative risk, 0.39; 95 percent confidence interval, 0.19 to 0.78) or estrogen alone (relative risk, 0.60; 95 percent confidence interval, 0.43 to 0.83). However, there was no significant associationbetween stroke and use of combined hormones (multivariate adjusted relative risk, 1.OQ;95 percent confidence interval, 0.66 to 1.80) or estro-
With
P.G. Taourel, M. Deneuville, JA Pradel, D. Regent, ].M. Bruel. Department of Medical Imaging, Hopital Saint-Eloi, Montpellier, France. Radiology I996;199:632-6.
Purpose: To evaluate the accuracy of dynamic, contrast material-enhanced computed tomography (CT) in the diagnoACC CURRENT
JOURNAL
REVIEW
87
MaddApnll997
IN
CONSULTATION
gen alone (relative risk, 1.27; 95 percent confidence interval, 0.95 to 1.69). Conclusions: The addition of progestin does not appear to attenuate the cardioprotective effects of postmenopausal estrogen therapy. Low Energy Internal Fibrillation Resistant
tricular premature contractions (VPCs), 556 + 1415. VPCs were multifocal in 9%, in runs in 25%, and early in 1%. In 29 (40%) of recordings, VPCs appeared mainly during and for several hours after HD. ST-T changes were seen in 43 (60%). In 11, ST depression occurred during and a few hours after HD. Patients receiving HD showed diverse ECG abnormalities. Holter ECGs revealed a high incidence of arrhythmias and ST-T changes, which frequently appeared in relation to HD timing.
Cardioversion of Atrial to Transthoracic Shocks
5. Hark Sopher, Francis D. Murgatroyd, Alistair K.B. Slade, Ivan Blankoff, Edward Rowland, David E. Ward, A. John Camm. St George’s Hospital and Medical School, Cranmer Terrace, London, Great Britain. Heart 1996;75:635-8.
Objective: To investigate the efficacy of internal cardioversion using low energy shocks delivered with a biatrial electrode configuration in chronic atria1 fibrillation resistant to transthoracic shocks. Methods: Low energy internal cardioversion was attempted in 11 patients who had been in atria1 fibrillation for 233 (SD 193) days and had failed to cardiovert with transthoracic shocks of 360 J in both apex-base and anteriorposterior positions. Synchronised biphasic shocks of up to 400 V (a6 J) were delivered, usually with intravenous sedation only, between high surface area electrodes in the right atrium and the left atrium (coronary sinus in nine, left pulmonary artery in one, left atrium via patent foramen ovale in one). Results: Sinus rhythm was restored in 8/11 patients. The mean leading edge voltage of successful shocks was 363 (46) V [4.9 (1.2) J]. Higher energy shocks induced transient bradycardia [time to first R wave 1955 (218) msl. No proarrhythmia or other acute complications were observed. Conclusions: Low energy internal cardioversion of atria1 fibrillation can restore sinus rhythm in patients in whom conventional transthoracic shocks have failed. Electrocardiographic Abnormalities Receiving Hemodialysis
Occult Ascending of an Air Bag
Aortic
Rupture
in the Presence
].A. Dunn, M.G. Williams. James H. Quillen College of Medicine, East Tennessee State Uniiersi~, Johnson City, TN. Ann Thorac Surg 1996621577-t.
A patient presented to the emergency department after a high-speed decelerating-type motor vehicle accident, Due to activation of his air bag device, the patient was without significant obvious injury. Upon evaluation in the emergency department he was also without any radiographic or physical signs of serious injury. In the ensuing 24 hours, severe chest pain developed, and subsequent aortography demonstrated a tear of his ascending aorta just distal to the root. Although occult injury to the aorta and great vessels does occur in a small percentage of patients, it is quite rare. However, with the advent of air bags, in the absence of associated injuries, signs, and symptoms, a high index of suspicion must be entertained in decelerating-type accidents to diagnose occult injury to the aorta and great vessels.
in Patients Long-Term Use of Nicotine Gum Is Associated With Hyperinsulinemia and Insulin Resistance
5. Abe, M. Yoshizawa, N. Nakanishi, T. Yazawa, K. Yokota, M. Honda, G. Sloman. Department of Internal Medicine, Keio Uniiersity, Tokyo, Japan. 1996;13 I:I 137-44.
B. Eliasson, M-R Taskinen, U. Smith. Lundberg lab. for Diabetes Research, Department of Internal Medicine, Sahlgrenska Universiq Hospital, Goteborg, Sweden. 1996;94:878-81.
We assessed standard 12-lead and Holter electrocardiographic (ECG) abnormalities in maintenance hemodialysis (HD) patients, Of 221 outpatients receiving HD, 143 (65%) had ECG abnormalities. Rates were higher in male, elderly, hypertensive, and diabetic patients than in female, younger, normotensive, and nondiabetic patients. The prevalence of ECG changes correlated inversely with HD duration. Serial ECGs were compared in 87 patients whose average HD duration was 7.5 5 2.5 years. Thirty-four patients (39%) showed normal ECGs throughout, 27 (31%) relatively stable abnormalities, 22 (25%) worsening, and 4 (5%) reversion to normal. Age, hypertension, and diabetes are factors related to abnormal ECG findings. Among the 142 Holter recordings from 72 patients, 70 (97%) were basically in sinus rhythm, and 2 (3%) were in atria1 fibrillation. The average frequency of supraventricular premature contractions (SVPCs) was 1597 ? 9725 per 24 hours, and that of venACC CURRENT
JOURNAL
Background: Insulin sensitivity and cardiovascular risk profile were examined in 20 healthy, nonobese, middle-aged men who were long-term users of nicotine-containing chewing gum and in 20 matched control subjects who did not use nicotine. Methods and Results: Long-term use of nicotinecontaining chewing gum was associated with insulin resistance and hyperinsulinemia. The degree of insulin sensitivity correlated negatively to the extent of nicotine use measured as plasma cotinine levels. Conclusions: These findings suggest that nicotine is the major constituent in cigarette smoke that leads to insulin resistance, metabolic abnormalities associated with the insulin resistance syndrome, and increased cardiovascular morbidity. Thus, the use of nicotine replacement therapy during smoking cessation should be transient and limited. REVIEW
88
March/April
1997