Israel Medical Association Journal

Background: Oral anticoagulation with warfarin can lead to life-threatening events as a result of either over-anticoagulation or undertreatment. One of the main contributors to an undesirable warfarin effect is the need to adjust its daily dose for a specific patient. The dose is adjusted empirically based on the experience of the clinician, a method that is often imprecise. There is currently no other well-accepted method for predicting the maintenance dose of warfarin.

Objective: To describe the application of an artificial neural network to the problem of warfarin maintenance dose prediction.

Methods: We designed a neural network that predicts the maintenance dose of warfarin. Data on 148 patients attending a large anticoagulant clinic were collected by file review. Using correlational analysis of the patients' data we selected the best input variables. The network was trained by using the back-propagation algorithm on a subset of our data and the results were validated against the rest of the data. We used a multivariate linear regression to create a comparable model.

Results: The neural network generated reasonable predictions of the maintenance dose (r = 0.823). The results of the linear regression model were similar (r = 0.800).

Conclusion: Neural networks can be applied successfully for warfarin maintenance dose prediction. The results are promising, but further investigation is needed.
 

Background: Hypertension is considered resistant if blood pressure cannot be reduced to <140/90 mmHg with an appropriate triple-drug regimen, including an oral diuretic, with all agents administered at maximal dosages. This definition has evolved with the development of new therapies and evidence-based data supporting treatment to lower BP[1] goals.

Objective: To assess whether vitamin C and atorvastatin improve endothelial function and blood pressure control in subjects with resistant arterial hypertension and dyslipidemia.

Methods: Forty-eight hyperlipidemic subjects with RH[2] (office systolic BP >140 mmHg and/or office diastolic BP >90 mm/Hg notwithstanding antihypertensive treatment with three medications in maximal doses) were randomized into three groups to receive additional medication for 8 weeks. Group VTC (n = 17) – mean 24 hour SBP[3] 150.6 ± 5.2 mmHg, DBP[4] 86.1 ± 3.3 mmHg, low density lipoprotein 158.1 ± 24.5 mg/dl) – received vitamin C 500 mg per day; Group ATR (n = 15) – mean 24 hour SBP 153.1 ± 4.8 mmHg, DBP 87.1 ± 6.7 mmHg, LDL[5] 162.6 ± 13.6 mg/dl) – received atorvastatin 20 mg/day; and Group PLA (n = 16) – mean 24 hour SBP 151.1 ± 7.4 mmHg, DBP 84.8 ± 5.9 mmHg, LDL 156.7 ± 26.1 mg/dl – received a placebo. High resolution ultrasound was used to calculate brachial artery flow-mediated dilation, and 24 hour ambulatory BP monitoring was performed at study entry and after 8 weeks.

Results: In the ATR group there were significant reductions of SBP (DSBP1-2: 13.7 ± 5.6 mmHg, P < 0.001), DBP (DDBP1-2: 7.8 ± 5.7 mmHg, P < 0.01), LDL (DLDL1-2: 67.7 ± 28.3 mg/dl, P < 0.001) and improvement of brachial artery FMD[6] (DFMD2-1: 4.2 ± 2.6%). No significant changes in BP, LDL and FMD were observed in the other two groups.

Conclusions: In subjects with RH and dyslipidemia, atorvastatin 20 mg/day compared to vitamin C 500 mg/day may help to achieve better BP control and improve endothelial function in a finite period. A larger trial is needed to assess the drug's efficacy in this population for longer periods.

Background: The physical properties of cancerous skin tissue have rarely been measured in either fresh or frozen skin specimens. Of interest are the elastic properties associated with the skin's ability to deform, i.e., to stretch and compress. Two constants – Young’s modulus and Poisson’s ratio – represent the basic elastic behavior pattern of any elastic material, including skin. The former relates the applied stress on a specimen to its deformation via Hooke’s law, while the latter is the ratio between the axial and lateral strains.

Objectives: To investigate the elastic properties of cancerous skin tissue. For this purpose 23 consecutive cancerous tissue specimens prepared during Mohs micrographic surgery were analyzed.

Methods: From these specimens we calculated the change in radial length (defined as the radial strain) and the change in tissue thickness (defined as axial strain).

Results: Based on the above two strains we determined a Poisson ratio of 0.43 ± 0.12 and an average Young modulus of 52 KPa.

Conclusions: Defining the elastic properties of cancerous skin may become the first step in turning elasticity into a clinical tool. Correlating these constants with the histopathologic features of a cancerous tissue can contribute an additional non-invasive, in vivo and in vitro diagnostic tool.

Background: Advances in surgical techniques and retractor-stabilizer devices allowing access to all coronary segments have resulted in increased interest in off-pump coronary artery bypass. The residual motion in the anastomotic site and potential hemodynamic derangements, however, render this operation technically more demanding.

Objectives: To evaluate the OPCAB[1] experience in a single Israeli center.

Methods: Between 2000 and 2003 in our institution, 1,000 patients underwent off-pump operations. Patients were grouped by the type of procedure, i.e., minimally invasive direct coronary artery bypass or mid-sternotomy OPCAB.

Results: One hundred MIDCAB[2] operations were performed. Of the 900 OPCAB, 767 patients received multiple grafts with an average of 2.6 ± 0.6 grafts per patient (range 2–4) and the remaining patients underwent single grafting during hybrid or emergency procedures. In the multiple-graft OPCAB group, complete revascularization was achieved in 96%. Multiple arterial conduits were used in 76% of the patients, and total arterial revascularization without aortic manipulation, using T-graft (35%) or in situ configurations, was performed in 61%. The respective rates for early mortality, myocardial infarction and stroke in the MIDCAB were 1%, 0% and 2%, and 2%, 1.3% and 0.9% in the multiple-vessel OPCAB groups. Multivariate analysis identified renal dysfunction (odds ratio 11.5, confidence interval 3.02–43.8; P < 0.0001) and emergency operation (OR[3] 8.74, CL[4] 1.99–38.3; P = 0.004) as predictors of mortality. The proportion of off-pump procedures increased from 9% prior to the study period to 59%.

Conclusions: The use of OPCAB does not compromise the ability to achieve complete myocardial revascularization. Our procedure of choice is OPCAB using arterial conduits, preferably the 'no-touch' aorta technique.

Background: The long-standing and ongoing controversy regarding administration of analgesia to patients with acute abdominal pain prior to final diagnosis has not yet been resolved, despite considerable research. Consequently, wide variations in clinical practice exist.

Objectives: To determine the motives, attitudes and practices of emergency physicians, internists and surgeons in Israeli emergency departments regarding the administration of analgesia before diagnosis in patients with acute abdominal pain.

Methods: Questionnaires were completed by 122 physicians in 21 EDs[1] throughout Israel and the replies were analyzed.

Results: Most EDs did not have a clear policy on analgesia for undifferentiated abdominal pain, according to 65% of the responders. More internists (75%) than surgeons (54%) (P = 0.02) and more emergency physicians (81%) than all other physicians (60%) (P = 0.05) held this opinion. Most respondents (64%) supported administration of analgesia pre-diagnostically. Support for analgesia was significantly stronger among internists (75%) compared to surgeons (52%) (P = 0.03). Despite this wide support, most respondents (68%) indicated that analgesia was rarely or never given pre‑diagnostically and, when it was, more surgeons (58%) than other physicians made that decision. Most internists (73%) and all surgeons reported that patients receive analgesia only after being examined by surgeons. Time allocated to the ED (part‑ or full‑time) significantly (P = 0.02) influenced decision-making, with 51% of part-time physicians vs. 25% of full-time opposing prompt administration of analgesia. Opinions on who should decide were divided according to medical specialty, with surgeons and internists almost opposed, as well as by physician age and percent of his/her time spent working in the ED. More surgeons than internists (P = 0.0005) reported that analgesia sometimes interfered with making a diagnosis. Most physicians (90%) stated that opiates impede diagnosis, to some extent. However, 58% of them supported the administration of opiates, more or less frequently. Intramuscular diclofenac was the most preferred analgesic, followed by intravenous morphine and pethidine; individual preferences extended beyond the list of actually administered drugs.

Conclusions: There is no consensus on the administration of analgesia for undiagnosed acute abdominal pain in EDs in Israel. Physicians’ attitudes are influenced by training, experience, and percent of personal time allocated to work in the ED.