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Biomedical subjects

R Davidoff

Publications and source records attributed to R Davidoff.

At least 37 records · Page 2Linked to original sources
PubMed1997

Multiple urinary cytokine levels of bacterial cystitis.

PURPOSE: We have examined urinary cytokine levels to define the inflammatory response in patients with bacterial cystitis or microhematuria relative to normal subjects. Cytokines examined include interleukin-1beta (IL-1beta), IL-1alpha, tumor necrosis factor (TNF alpha), IL-6 and IL-4. Unique features of this study include a) a simultaneous study of several relevant cytokines b) a study of the inflammatory response at both low and high counts of bacterial infection and c) an assessment of whether microhematuria without bacterial cystitis or pyuria is associated with cytokine elevation compared to normals. MATERIALS AND METHODS: Enzyme immunoassays were utilized for each cytokine. Patients studied include those with bacterial cystitis (n = 49), patients with microhematuria (n = 11), and normal subjects (n = 36). Cytokine levels were also determined for patients with low count bacterial cystitis (1,000-50,000 organisms; n = 15) and compared to high count bacterial cystitis (>100,000 organisms; n = 34) and normal subjects. Statistical analysis was carried out using the Kruskal-Wallis test followed by pairwise testing with Newman-Keuls test. RESULTS: a) The means for normal, microhematuria and bacterial cystitis groups were significantly different (p <0.05) for IL-1beta, IL-1alpha, TNF alpha and IL-6, but not for IL-4. b) Except for IL-4, all cytokines were found to be significantly elevated in low count bacterial cystitis compared to normals. No statistically significant difference was observed between low and high count bacterial cystitis groups for any of the cytokines tested. CONCLUSIONS: a) Significant and similar inflammatory responses are present in both low and high count bacterial cystitis groups as compared with the normal group. b) IL-6 and TNF alpha are significantly elevated in patients with microhematuria compared to normals. c) The potential clinical utility of the assays lies in identifying the specific cytokines elevated, understanding the pathways that give rise to their production, and in defining potential virulence factors that may produce significant inflammation at low count bacterial infections.

Colony Count, Microbial↗
PubMed1997

Influence of technique of percutaneous tract creation on incidence of renal hemorrhage.

PURPOSE: Renal hemorrhage is one of the most common and worrisome complications of percutaneous renal surgery. We studied the incidence of renal hemorrhage and transfusion rates in patients undergoing balloon or Amplatz fascial dilation of the nephrostomy tract. MATERIALS AND METHODS: Medical records of 143 patients who underwent 150 percutaneous renal procedures, including percutaneous nephrolithotomy, antegrade endopyelotomy and percutaneous treatment of stones in caliceal diverticula, were reviewed. The nephrostomy tract was dilated with balloon (50 patients) or Amplatz sequential (100) dilators. Perioperative decreases in hemoglobin level and blood transfusion rates were compared between the 2 groups. RESULTS: Of the 100 patients undergoing percutaneous renal Amplatz dilation 25 (25%) required a blood transfusion, compared to only 5 of 50 (10%) undergoing balloon dilation. The difference in the transfusion rates between the 2 groups was statistically significant (p = 0.048). CONCLUSIONS: Improvements in the technique of percutaneous renal surgery have decreased the morbidity associated with these procedures. In our study use of balloon tract dilators led to less renal hemorrhage and lower transfusion rates compared to Amplatz dilation. Additionally, balloon dilation appears to be more rapid and avoids renal movement away from the surgeon, which occasionally occurs during Amplatz dilation.

Adolescent↗
PubMed1997

"Tubeless" percutaneous surgery: a new advance in the technique of percutaneous renal surgery.

We describe our modification of the technique of traditional percutaneous renal surgery called "tubeless" percutaneous renal surgery. Fifty patients have now undergone percutaneous renal procedures without the use of a postoperative nephrostomy tube consisting of percutaneous nephrolithotripsy, percutaneous endopyelotomy, and both percutaneous stone extraction and endopyelotomy in the same setting. Our current modification of standard percutaneous surgical technique includes the placement of an internal ureteral catheter with primary closure of the access site using hemostatic skin sutures. The study group was compared to a control group of 50 patients who were age, sex and procedure matched who had undergone standard percutaneous renal procedures previously with routine placement of postoperative nephrostomy tubes. The incidence of complications, analgesia requirements, length of hospitalization, time of return to normal activities, and cost of treatment were compared between the two groups. All tubeless percutaneous procedures were successfully performed without significant complications. The initial 15 patients had postoperative renal ultrasounds demonstrating no urinoma. Hospital stay, analgesia requirements, and the patient's ability to return to normal activities were statistically significantly decreased in the patient group studied. The cost of a "tubeless" procedure was $1,638 compared with $3,750 (129% greater) for traditional percutaneous surgery (cost saving of $2,112/case). Tubeless percutaneous renal surgery is a safe procedure and offers advantages over the routine placement of a nephrostomy tube. The hospitalization period, analgesia requirements, return to normal activities, and cost are significantly less with this new technique.

Activities of Daily Living↗
PubMed1996

Comparison of the usefulness of Doppler pressure half-time in mitral stenosis in patients < 65 and > or = 65 years of age.

Doppler pressure half-time is a reliable method for estimating mitral valve area when net left atrial and ventricular compliance remain stable. The accuracy of Doppler pressure half-time in estimating mitral valve area in older patients is unknown. We studied 80 patients (65 women and 15 men, aged 56 +/- 14 years) with cardiac catheterization and echocardiography. Mitral valve area was calculated using the Gorlin formula and by the Doppler pressure half-time method. Patients were stratified into those aged < 65 years (n = 57), and those aged > or = 65 years (n = 23). The discordance between pressure half-time and Gorlin-derived mitral valve area was assessed and related to multiple clinical, echocardiographic, and hemodynamic variables. The difference between pressure half-time and Gorlin-derived mitral valve area was greater in the older than in the younger patient (0.34 +/- 0.30 vs 0.15 +/- 0.27 cm2, p = 0.009) but the older group had smaller mitral valve areas by the Gorlin method (0.72 +/- 0.18 vs 0.89 +/- 0.32 cm2, p = 0.02) and lower cardiac output. The difference between pressure half-time and Gorlin remained greater in the group of older patients (0.32 +/- 0.30 vs 0.19 +/- 0.22 cm2, p = 0.04), even when the analysis was restricted to patients with similar mitral valve area (< 1 cm2 by the Gorlin method). Using multivariate analysis, age > or = 65 years remained the only significant predictor of the discrepancy between pressure half-time and Gorlin mitral valve area. Thus, when compared with Gorlin-derived mitral valve area, pressure half-time overestimated valve area in older patients, and this technique for estimating mitral valve area should be used with caution in patients > or = 65 years of age.

Age Factors↗
PubMed1996

Left atrial myxoma and acute myocardial infarction. A dangerous duo in the thrombolytic agent era.

Systemic embolization is a common complication of left atrial myxoma; however, coronary embolism leading to acute myocardial infarction is rare. The use of echocardiography has increased the detection of intracardiac tumors when signs and symptoms are not evident. Echocardiography is the diagnostic procedure of choice in the initial evaluation of patients with suspected left atrial myxoma.

Echocardiography↗
PubMed1995

Prevention of embolic events after cardioversion of atrial fibrillation. Current and evolving strategies.

We review the incidence of embolic events following cardioversion of atrial fibrillation, as well as the literature that forms the basis for the current strategy of anticoagulation before, and following, cardioversion to reduce the risk of post-cardioversion embolism. We evaluate a new strategy that uses transesophageal echocardiography to identify patients in atrial fibrillation without atrial thrombi who may be safely cardioverted without preceding anticoagulation and we also address the embolic event and anticoagulation issues in patients with atrial flutter. Cardioversion of atrial fibrillation to sinus rhythm is associated with a small but significant risk of thromboembolic events (average incidence, 1.5%; range, 0% to 7%). Anticoagulating these patients before cardioversion appears to significantly reduce this risk, and because of the delay in return of atrial contraction, anticoagulation should be continued for several weeks following cardioversion. The current guidelines for anticoagulating patients in atrial fibrillation who are to be cardioverted is based primarily on clinical observations, numerous uncontrolled case series, two retrospective trials, and one prospective nonrandomized controlled trial. Anticoagulation for 3 weeks before cardioversion followed by 4 weeks of anticoagulation after cardioversion is a theoretically sound and effective approach to reduce the risk of thromboembolic events. The use of transesophageal echocardiography to rule out thrombus and thus identify low-risk patients who may undergo cardioversion without preceding anticoagulation has been supported by several small studies that successfully used this strategy. However, the demonstration of a postcardioversion atrial and atrial appendage "stunning" suggests that anticoagulation needs to be given at the time of, and following, cardioversion. While promising, this transesophageal echocardiography--guided strategy for cardioversion of patients in atrial fibrillation requires more rigorous study before its routine use can be recommended. The current management of pure atrial flutter requires no anticoagulation before cardioversion; however, several clinical observation suggest theoretical risks for embolic events in these patients, thus further investigation of this strategy may be warranted.

Anticoagulants↗
PubMed1995

Right coronary artery stenosis: an independent predictor of atrial fibrillation after coronary artery bypass surgery.

OBJECTIVES: This study attempted to determine the importance of severe proximal right coronary artery disease as a predictor of atrial fibrillation in patients after coronary artery bypass surgery. BACKGROUND: Studies in patients undergoing noncardiac surgery have suggested that ischemia in the right coronary artery distribution is associated with a high incidence of atrial fibrillation. However, the importance of right coronary artery disease as a predictor of atrial fibrillation after bypass surgery is unknown. METHODS: The occurrence of sustained postoperative atrial fibrillation was studied prospectively in 168 consecutive patients undergoing coronary artery bypass grafting. Patients were followed up postoperatively until discharge. Severe right coronary artery stenosis was defined as > or = 70% lumen narrowing. RESULTS: Of 104 patients with proximal or mid right coronary artery stenosis, 45 (43%) had atrial fibrillation postoperatively compared with 12 (19%) of the 64 patients without significant right coronary disease (p = 0.001). Univariate predictors of atrial fibrillation included right coronary artery stenosis (p = 0.001), advancing age (p = 0.0001) and lack of beta-adrenergic blocking agent therapy after bypass surgery (p = 0.0004). Multivariate adjusted risk of developing atrial fibrillation after bypass surgery increased with the presence of severe right coronary artery disease (odds ratio 3.69, 95% confidence interval [CI] 1.61 to 8.48), advancing age (odds ratio 2.24/10 years, CI 1.48 to 3.41) and male gender (odds ratio 2.36, CI 1.01 to 5.49). The use of beta-blockers postoperatively was associated with a protective effect (odds ratio 0.4, CI 0.17 to 0.80). CONCLUSIONS: The presence of severe right coronary artery stenosis is an independent and powerful predictor of atrial fibrillation after coronary artery bypass surgery. In association with age, gender and postoperative beta-blocker therapy, these variables can be used to identify patients at increased risk for developing this arrhythmia.

Aged↗
PubMed1995

Acute, reversible left ventricular dysfunction in status asthmaticus.

Three cases of rapidly reversible severe myocardial depression are described in patients with status asthmaticus. Initial echocardiograms obtained within 1 day of hospital admission revealed global left ventricular hypokinesis with ejection fractions of 11 to 34%. Follow-up echocardiograms obtained only 3 to 8 days later revealed marked improvement of left ventricular function. Possible mechanisms responsible for the observed rapidly reversible myocardial depression and the clinical implications of this finding are discussed.

Adult↗
PubMed1994

Increased left ventricular diastolic chamber stiffness immediately after coronary artery bypass surgery.

OBJECTIVES: The aim of this study was to assess the incidence and severity of left ventricular diastolic dysfunction immediately after coronary artery bypass surgery by utilizing simultaneous transesophageal echocardiographic and hemodynamic monitoring. BACKGROUND: Left ventricular diastolic dysfunction has been documented after coronary bypass surgery, but its measurement has been technically difficult to acquire and limited by dependence on loading conditions. METHODS: End-diastolic pressure-area curves were constructed before and immediately after coronary bypass surgery in 20 patients. Transesophageal echocardiographic images at the midpapillary level of the left ventricle and hemodynamic data were recorded. Volume status was manipulated to alter loading conditions, and multiple measurements were taken at each loading condition. RESULTS: Diastolic function worsened in all patients, as manifested by a postoperative leftward shift of the end-diastolic pressure-area curve. At a comparable preload, mean end-diastolic area +/- SEM decreased by 15% from 17.6 +/- 0.8 to 14.9 +/- 0.8 cm2 postoperatively (p = 0.0001). CONCLUSIONS: Left ventricular diastolic chamber stiffness frequently increases immediately after coronary artery bypass surgery. Simultaneous hemodynamic and transesophageal echocardiographic monitoring, through the construction of end-diastolic pressure-area curves, is a useful method to evaluate diastolic function and guide management after cardiac surgery.

Aged↗
PubMed1994

Spatial and temporal variability in the pattern of recovery of ventricular geometry and function after acute occlusion and reperfusion.

Myocardial ischemia and infarction are known to cause changes in both ventricular shape and function. Little is known about the recovery of ventricular geometry after transient myocardial ischemia and its relationship to recovery of function. To examine the pattern of recovery of ventricular geometry following transient coronary artery occlusion and to assess the relationship of this to the return of systolic function, we used echocardiography to study 13 dogs following 15-minute occlusion of the left anterior descending coronary artery. During ischemia, total endocardial surface area (ESA) increased from 32.55 +/- 1.77 to 45.36 +/- 3.18 cm2 (p = 0.001). The most striking increase was at the apex, where circumference increased from 5.04 +/- 0.24 at baseline to 7.86 +/- 0.43 cm at the end of occlusion (p = 0.0001), an increase of 58%. During reperfusion, ventricular geometry rapidly returned toward normal (baseline), with recovery of 80% of the increase in ESA evident by 15 minutes of reperfusion. Recovery of systolic function was substantially slower (p < 0.005 for all periods of observation during the 2 hours of reperfusion). During reperfusion, recovery of ventricular geometry and function was not uniform throughout the ischemic bed. The apex recovered most slowly, with the centroid of the area of abnormal contraction progressively moving along the long axis of the left ventricle toward the apex. There was also a progressive decrease in the radius of the area of dysfunction, from 2.0 +/- 0.15 at end occlusion to 0.13 +/- 0.07 cm at 120 minutes of reperfusion (p = 0.0001). There was no difference in blood flow between the apical and anterior segments during ischemia or reperfusion. Reperfusion favorably reduced the ischemic zone dilation before recovery of active systolic function and geometric recovery thus may be important in determining ultimate functional recovery. In addition, recovery of function proceeded inward towards the center of the ischemic territory and in a wavefront from the base to apex. This heterogeneous and asymmetric recovery suggests that sampling at one point within the ischemic zone may not reflect the true temporal pattern of recovery.

Acute Disease↗
PubMed1994

Right ventricular dysfunction: an independent predictor of adverse outcome in patients with myocarditis.

To assess the predictive value of right ventricular systolic function in patients with active myocarditis, the echocardiograms of 23 patients with biopsy-confirmed myocarditis were reviewed. Right ventricular systolic function was evaluated qualitatively and quantitatively by descent of the right ventricular base. Patients were divided into those with normal right ventricular function, in whom right ventricular descent was 1.9 +/- 0.1 cm, and those with abnormal right ventricular function, in whom right ventricular descent was 0.8 +/- 0.1 cm (p < 0.001). There were no differences between the two groups in age, duration of symptoms, baseline hemodynamics, or histologic assessment. Initial left ventricular ejection fraction was significantly lower in patients with depressed right ventricular function (27.5 +/- 4.9%) compared with that in patients with normal right ventricular function (47.5 +/- 6.3%) (p = 0.01). The likelihood of an adverse outcome, defined as death or need for cardiac transplantation, was greater in patients with abnormal right ventricular function (right ventricular descent < or = 1.7 cm) than in patients with normal right ventricular function (right ventricular descent > 1.7 cm) (p < 0.03). Multivariate analysis revealed that right ventricular dysfunction as quantified by right ventricular descent was the most powerful predictor of adverse outcome.

Female↗
PubMed1992

Effects of dobutamine on Gorlin and continuity equation valve areas and valve resistance in valvular aortic stenosis.

Previous studies demonstrated changes in aortic valve area calculated by the Gorlin equation under conditions of varying transvalvular flow in patients with valvular aortic stenosis (AS). To distinguish between flow-dependence of the Gorlin formula and changes in actual orifice area, the Gorlin valve area and 2 other measures of severity of AS, continuity equation valve area and valve resistance, were calculated under 2 flow conditions in 12 patients with AS. Transvalvular flow rate was varied by administration of dobutamine. During dobutamine infusion, right atrial and left ventricular end-diastolic pressures decreased, left ventricular peak systolic pressure and stroke volume increased, and systolic arterial pressure did not change. Heart rate increased by 19%, cardiac output by 38% and mean aortic valve gradient by 25%. The Gorlin valve area increased in all 12 patients by 0.03 to 0.30 cm2. The average Gorlin valve area increased from 0.67 +/- 0.05 to 0.79 +/- 0.06 cm2 (p < 0.001). In contrast, the continuity equation valve area (calculated in a subset of 6 patients) and valve resistance did not change with dobutamine. The data support the conclusion that flow-dependence of the Gorlin aortic valve area, rather than an increase in actual orifice area, is responsible for the finding that greater valve areas are calculated at greater transvalvular flow rates. Valve resistance is a less flow-dependent means of assessing severity of AS.

Aged↗
PubMed1991

Echocardiographic assessment of patients with infectious endocarditis: prediction of risk for complications.

To enhance the echocardiographic identification of high risk lesions in patients with infectious endocarditis, the medical records and two-dimensional echocardiograms of 204 patients with this condition were analyzed. The occurrence of specific clinical complications was recorded and vegetations were assessed with respect to predetermined morphologic characteristics. The overall complication rates were roughly equivalent for patients with mitral (53%), aortic (62%), tricuspid (77%) and prosthetic valve (61%) vegetations, as well as for those with nonspecific valvular changes but no discrete vegetations (57%), although the distribution of specific complications varied considerably among these groups. There were significantly fewer complications in patients without discernible valvular abnormalities (27%). In native left-sided valve endocarditis, vegetation size, extent, mobility and consistency were all found to be significant univariate predictors of complications. In multivariate analysis, vegetation size, extent and mobility emerged as optimal predictors and an echocardiographic score based on these factors predicted the occurrence of complications with 70% sensitivity and 92% specificity in mitral valve endocarditis and with 76% sensitivity and 62% specificity in aortic valve endocarditis.

Adult↗
PubMed1991

Giant cell versus lymphocytic myocarditis. A comparison of their clinical features and long-term outcomes.

BACKGROUND: Giant cell myocarditis has rarely been diagnosed premortem, and little is known about its natural history. In addition, no comparative studies with lymphocytic myocarditis exist. METHODS AND RESULTS: The clinical features, serial change in left ventricular fraction (LVEF), and outcomes of all patients with histologically verified myocarditis were retrospectively evaluated. Ten patients (22%) were found to have giant cell myocarditis (group 1), whereas the remaining 36 (78%) had lymphocytic myocarditis (group 2). Age at presentation, gender distribution, duration of symptoms, initial LVEF, and resting hemodynamics did not differ between groups. Ventricular tachycardia was detected in 90% of group 1 patients compared with only 25% of group 2 (p = 0.0007). Atrioventricular block that required pacemaker insertion was also more common in group 1 (60%) than in group 2 (8.3%) (p = 0.001). Left ventricular systolic function declined during follow-up in group 1 patients (LVEF, 0.43 +/- 0.07-0.26 +/- 0.05, p = 0.11) but increased in group 2 patients (LVEF, 0.33 +/- 0.03-0.41 +/- 0.03, p = 0.02). When the net change between initial and final LVEF was assessed, a significant difference was evident (giant cell group, -0.17 +/- 0.06; lymphocytic group, +0.07 +/- 0.03; p = 0.0008). Although a greater proportion of patients in group 1 died or required transplantation (seven of 10 versus 11 of 36, p = 0.03), actuarial survival over 4 years was not different for the giant cell group (50%) than for the lymphocytic group (62%). CONCLUSION: Giant cell myocarditis was more prevalent than previously recognized and highly associated with both ventricular tachycardia and pacemaker requirement. The likelihood of an adverse event, either cardiovascular mortality or cardiac transplantation, was significantly greater for patients with giant cell myocarditis than for those with lymphocytic myocarditis, perhaps because of the progressive decline in left ventricular systolic function that was observed in those with giant cell myocarditis.

Adult↗
PubMed1990

Aggression and counteraggression during child psychiatric hospitalization.

The article reports on a 1-year descriptive study of aggressive incidents and staff counteraggressive strategies within a child psychiatry inpatient unit. Ninety-nine child/adolescent patients produced a total of 887 reportable aggressive incidents during the 12-month study period. Seclusion, activity restriction, physical restraint, and administration of p.r.n. medication were studied in relation to patient aggression. Results of the study confirm the hypotheses that (1) much patient aggression within defined clinical contexts conforms to patterns of prediction directly related to person and environmental variables, and (2) the primary value of counteraggression strategies such as seclusion and restraint resides in the acute management of aggressive children and not in long-term therapeutic functions. The article offers some recommendations for new research in this general area as well as suggestions for clinical applications of these methods.

Aggression↗