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Biomedical subjects

M Mehta

Publications and source records attributed to M Mehta.

At least 37 records · Page 2Linked to original sources
PubMed2001

Privately funded quality health care in India: a sustainable and equitable model.

OBJECTIVE: As the cost and degree of training necessary to provide state of the art health care has increased throughout the world, the present challenge in health care is to establish institutions that are financially sound and responsive to the dynamic needs of the communities in which they exist. As public funds have diminished, the role of the private sector in estabhshing innovative health care institutions has increased. SETTING AND STUDY PARTICIPANTS: This paper reviews the case of the LV Prasad Eye Institute (LVPEI), an ophthalmologic institute in Hyderabad, India, that is financially sound and medically vital. With an annual budget of US$3 million, 180 000 patients are seen and 23 000 surgeries are performed at the Institute and its satellites each year. MAIN MEASURES: The Institute provides patient care at a ratio of 1:1 non-paying to paying patients through fee cross-subsidization. The Institute uses a combination of financial modalities, including donations, grants and fees to administer its non-patient care programs. Non-clinical programs of the Institute include a paramedical training program and a fellowship in ophthalmology, an internationally accredited eye bank for the preservation of corneal tissues, a rural out-reach and education program, a basic science and epidemiology program that directs health policy activities of the Institute and a rehabilitation program for patients with incurable visual deficits. To evaluate its effectiveness, LVPEI uses quality improvement measures, including patient surveys, post-operative outcomes studies and service utlization reviews. CONCLUSION: This case report of a privately-funded medical institution describes a successful model through which high-quality, equitable health care can be provided in a developing country. The LVPEI's active program of quality management, its academic commitment and programmatic relevance to the needs of its community should be modularized and replicated to establish equitable, efficient and effective health care institutions in the developing world.

Budgets↗
PubMed2001

Increasing incidence of midterm and long-term complications after endovascular graft repair of abdominal aortic aneurysms: a note of caution based on a 9-year experience.

OBJECTIVE: To analyze the late complications after endovascular graft repair of elective abdominal aortic aneurysms (AAAs) at the authors' institution since November 1992. SUMMARY BACKGROUND DATA: Recently, the use of endovascular grafts for the treatment of AAAs has increased dramatically. However, there is little midterm or long-term proof of their efficacy. METHODS: During the past 9 years, 239 endovascular graft repairs were performed for nonruptured AAAs, many (86%) in high-risk patients or in those with complex anatomy. The grafts used were Montefiore (n = 97), Ancure/EVT (n = 14), Vanguard (n = 16), Talent (n = 47), Excluder (n = 20), AneuRx (n = 29), and Zenith (n = 16). All but the AneuRx and Ancure repairs were performed as part of a U.S. phase 1 or phase 2 clinical trial under a Food and Drug Administration investigational device exemption. Procedural outcomes and follow-up results were prospectively recorded. RESULTS: The major complication and death rates within 30 days of endovascular graft repair were 17.6% and 8.5%, respectively. The technical success rate with complete AAA exclusion was 88.7%. During follow-up to 75 months (mean +/- standard deviation, 15.7 +/- 6.3 months), 53 patients (22%) died of unrelated causes. Two AAAs treated with endovascular grafts ruptured and were surgically repaired, with one death. Other late complications included type 1 endoleak (n = 7), aortoduodenal fistula (n = 2), graft thrombosis/stenosis (n = 7), limb separation or fabric tear with a subsequent type 3 endoleak (n = 1), and a persistent type 2 endoleak (n = 13). Secondary intervention or surgery was required in 23 patients (10%). These included deployment of a second graft (n = 4), open AAA repair (n = 5), coil embolization (n = 6), extraanatomic bypass (n = 4), and stent placement (n = 3). CONCLUSION: With longer follow-up, complications occurred with increasing frequency. Although most could be managed with some form of endovascular reintervention, some complications resulted in a high death rate. Although endovascular graft repair is less invasive and sometimes effective in the long term, it is often not a definitive procedure. These findings mandate long-term surveillance and prospective studies to prove the effectiveness of endovascular graft repair.

Aged↗
PubMed2001

Limited role for IVUS in the endovascular repair of aortoiliac aneurysms.

BACKGROUND: To determine the need for routine versus selective intraoperative IVUS during endovascular aortoiliac aneurysm (AIA) repair. METHODS: One-hundred and eighty-eight endovascular AIA repairs performed over a 5-year period were reviewed and included in the study. Surgeon-made aorto-uni-femoral grafts (n=78) and industry-made bifurcated or tube grafts (n=110) were used. In the initial 51 cases IVUS was routinely performed. In the latter 137 cases IVUS was used selectively. In this group graft deformities suspected on completion angiography or pullback pressure measurements were treated with balloon dilatation and stenting. IVUS was then performed only in the presence of a persistent pressure gradient or inconclusive angiographic findings. RESULTS: In the initial 51 cases IVUS revealed 20 lesions of which 8 were not initially detected angiographically and which required further treatment. In the latter 137 cases IVUS was necessary in only 1 case, and guided the treatment of an angiographically undetectable lesion. There have been no late episodes of graft compression, kinking, or thrombosis in the selective IVUS group. CONCLUSIONS: The use of pullback pressure measurements with a low threshold for angioplasty and stenting, especially in unsupported grafts, followed by the selective use of IVUS decreases the overall requirement for IVUS and its associated costs.

Angiography↗
PubMed2001

Epidemiological investigation of cholera outbreak in a periurban slum colony in Chandigarh.

An investigation was carried out in a periurban slum colony in Chandigarh in September 1999 following a report of two microscopically confirmed cases of cholera admitted in Govt. Medical College Hospital, Chandigarh. Rapid survey in the colony covering a population of 1404 found that there were 14 cases of diarrhoea in the colony with attack rate of 9.97/1000 population. Majority (70%) of cases were females and 62% cases were under five years of age. Health education, ORS packets and medications were distributed to cases. Water sampling was also done and it was found that water from one of the hand pump was positive for V. cholerae 01 biotype El Tor serotype Ogawa. Closing of that hand pump and chlorination of drinking water in other parts of slum was recommended to higher health authorities, which was done immediately. Surveillance for diarrhoeal diseases was found to be poor. Provision of safe drinking water, improving sanitation and strengthening of disease surveillance is necessary for control of cholera and other diarrhoeal diseases in slum areas.

Child↗
PubMed2000

A phase II study of preradiation chemotherapy followed by external beam radiotherapy for the treatment of patients with newly diagnosed glioblastoma multiforme: an Eastern Cooperative Oncology Group study (E2393).

Recent publications support the use of preradiation chemotherapy in the treatment of selected primary brain tumors. In the pediatric population, this treatment strategy often delays radiotherapy and may improve the outcome in patients. This manuscript describes the use of a preradiation chemotherapy approach for adult patients with newly diagnosed glioblastoma multiforme. The main objective of this trial was to determine the feasibility of delivering up to 3 monthly cycles of a 72 h continuous simultaneous intravenous infusion of BCNU (40 mg/m2/day) and cisplatin (40 mg/m2/day). Patients were evaluated for tumor response or progression after each cycle. Following the completion of the chemotherapy treatments or evidence of tumor progression, patients underwent external beam radiotherapy. A dose of 45 Gy was delivered to the pretreatment tumor volume plus surrounding edema and a margin of 3.0 cm. An additional 14.4 Gy was delivered to the preoperative volume plus a 2 cm margin. Fifty patients were enrolled, 47 were eligible and analyzable. Overall, 79% of patients were able to complete at least 2 cycles of treatment, exceeding the predefined measure of feasibility. One patient achieved a complete response, 10 patients a partial response and 18 patients had stable disease at completion of the chemotherapy treatments. Twenty-four patients experienced grade 4 toxicity, mostly hematologic. All patients were able to undergo radiotherapy following chemotherapy. These results indicate that a preradiation strategy is feasible. Although responses to the chemotherapy were seen, a phase III trial is needed to determine whether this approach provides an advantage over standard treatment; such a phase III trial has been undertaken by ECOG.

Adult↗
PubMed2000

Efficacy of percutaneous vas occlusion compared with conventional vasectomy.

OBJECTIVES: To determine the efficacy, evaluate the safety and assess side-effects (swelling, haematoma and pain) of percutaneous vas occlusion compared with vasectomy in Dutch men. PATIENTS AND METHODS: Vas occlusion and vasectomy procedures (attempted in 58 and 50 men, respectively) were conducted at the University Hospital Maastricht. The men returned 1 week after the procedure, underwent a clinical examination and completed a questionnaire assessing subjectively any pain, swelling and haematoma. The men were asked to return for semen analysis at 6 and 12 weeks and, if necessary, for additional analyses until they were azoospermic. RESULTS: The vas occlusion procedure was completed on both vasa in 49 of the 58 men (84%) in whom it was attempted. Significantly more (P < 0.001) men were azoospermic after vasectomy (48 of 50) than after vas occlusion (only four). Men undergoing vas occlusion reported significantly less pain (P = 0.02), swelling (P = 0.01) and haematoma (P = 0.04) after the procedure than did men undergoing vasectomy. CONCLUSION: Men undergoing vas occlusion would not have been able to rely on the method for contraception. From this study, vas occlusion, at least in its current form, is an unsuitable method of male contraception. Not only was the efficacy poor, but constraints in delivering the method in its current state would probably limit its utility, especially in situations where resources are limited.

Follow-Up Studies↗
PubMed2000

Does the endovascular repair of aortoiliac aneurysms pose a radiation safety hazard to vascular surgeons?

OBJECTIVES: Endovascular aortoiliac aneurysm (EAIA) repair uses substantial fluoroscopic guidance that requires considerable radiation exposure. Doses were determined for a team of three vascular surgeons performing 47 consecutive EAIA repairs over a 1-year period to determine whether this exposure constitutes a radiation hazard. METHODS: Twenty-nine surgeon-made aortounifemoral devices and 18 bifurcated devices were used. Three surgeons wore dosimeters (1) on the waist, under a lead apron; (2) on the waist, outside a lead apron; (3) on the collar; and (4) on the left ring finger. Dosimeters were also placed around the operating table and room to evaluate the patient, other personnel, and ambient doses. Exposures were compared with standards of the International Commission on Radiological Protection (ICRP). RESULTS: Total fluoroscopy time was 30.9 hours (1852 minutes; mean, 39.4 minutes per case). Yearly total effective body doses for all surgeons (under lead) were below the 20 mSv/y occupational exposure limit of the ICRP. Outside lead doses for two surgeons approximated recommended limits. Lead aprons attenuated 85% to 91% of the dose. Ring doses and calculated eye doses were within the ICRP exposure limits. Patient skin doses averaged 360 mSv per case (range, 120-860 mSv). The ambient (> 3 m from the source) operating room dose was 1.06 mSv/y. CONCLUSIONS: Although the total effective body doses under lead fell within established ICRP occupational exposure limits, they are not negligible. Because radiation exposure is cumulative and endovascular procedures are becoming more common, individuals performing these procedures must carefully monitor their exposure. Our results indicate that a team of surgeons can perform 386 hours of fluoroscopy per year or 587 EAIA repairs per year and remain within occupational exposure limits. Individuals who perform these procedures should actively monitor their effective doses and educate personnel in methods for reducing exposure.

Aortic Aneurysm↗
PubMed2000

Field-induced transitions and spatial chaos in the classical XY spin chain

We study the lowest-lying excitation of a classical ferromagnetic XY spin chain, in the presence of a symmetry breaking magnetic field. Extremizing the energy of this system leads to a two-dimensional nonlinear map, whose allowed phase space shrinks with increasing field in a nontrivial manner. The orbits of the map represent the set of extremum energy spin configurations. For each field, we compute the energy of the members of this set and find the lowest energy among them, excluding the obvious ground state configuration with all spins parallel along the field direction. This state turns out to be the unstable fixed point of the map. We show that up to a certain (primary) critical field, a separatrixlike 2pi soliton configuration is the lowest-energy excitation, with an energy very close to the ground state energy. For any field beyond this critical field, the soliton disappears and lowest excitation is a librational configuration corresponding to the outermost orbit in the phase plot at that field. Further, its energy is found to be much higher than the ground state energy, leading to a sharp jump in the difference in energy between the former and the latter at this field. With further increase in the field, sharp jumps in the excitation energy arise at certain secondary critical fields as well. We show that these appear when the corresponding spin configurations become commensurate. This complex behavior of the energy is interpreted and its effect on the magnetization and static susceptibility of the system is also studied.

Journal Article↗
PubMed2000

Complications of total hip arthroplasty: MR imaging-initial experience.

PURPOSE: To investigate the use of standard magnetic resonance (MR) imaging sequences with simple parameter modifications for the detection and characterization of total hip arthroplasty (THA) complications. MATERIALS AND METHODS: An initial phantom study was performed with cobalt-chrome and titanium prostheses to establish the imaging parameters for a subsequent clinical study. In the clinical study, coronal and transverse MR imaging of 14 THA prostheses was performed before and after intravenous contrast material administration in 12 patients who were being considered for revision arthroplasty. The images were reviewed for evidence of juxtaarticular or periprosthetic abnormalities, patterns of contrast enhancement, and quality of periprosthetic tissue depiction. RESULTS: Phantom study results showed improved periprosthetic tissue depiction with use of thin sections, increased frequency-encoding gradient strength, and fast spin-echo sequences. The clinical study results demonstrated periprosthetic abnormalities in 11 cases: mechanical loosening in two cases (including one case with an associated periprosthetic fracture); granulomatosis, eight; and infection, one. In 100% of cases, tissue depiction around the femoral component was judged to be of "diagnostic quality." Tissue depiction around the acetabular component was of diagnostic quality in five (36%) cases. In all seven surgically confirmed cases, a correct diagnosis was made preoperatively with MR imaging. CONCLUSION: By using simple modifications to standard MR imaging sequences, diagnostic-quality MR imaging of THA complications can be performed, particularly around the femoral prosthetic stem.

Acetabulum↗
PubMed1999

Early repolarization.

Early repolarization (ER) is an enigma. The purpose of this review is to reemphasize the overall electrocardiographic (ECG) pattern of this normal ST variant which continues to challenge the clinician because of its similarity to the current of injury potential to myocardium or an acute pericarditis. The data were provided from the studies identified through computerized searches of Medline, Toxline, Oxford, Agricola, and Bios Afterdark, Cumulative index, and a review of bibliographies of relevant articles on the related subjects. Early repolarization has elevated, upward, concave ST segments, located commonly in precordial leads, with reciprocal depression in a VR, tall, peaked and slightly asymmetrical T waves with notch, and slur on the R wave. The other accompanying features in the ECG are vertical axis, shorter and depressed P-R interval, abrupt transition, counterclockwise rotation, presence of U waves, and sinus bradycardia. Males dominate and patients are often younger than 50 years of age. The incidence of 1 to 2% is found equally common in all races. Degree and incidence of ST elevation decrease as age advances. Exercise or isoproterenol administration may normalize the ST segment. Early repolarization is a benign condition. If the ECG conforms to a classical pattern of ER on serial ECGs, it would exclude the unnecessary hazards of present day revascularization therapy for myocardial infarction such as primary angioplasty or thrombolytic therapy, or aggressive management of acute pericarditis, and so forth. This review concludes with a discussion of comparative ECG features of ER, pericarditis, and myocardial infarction, and provides an algorithm for diagnostic management of patients suffering from these conditions.

Acute Disease↗
PubMed1999

Constrictive pericarditis.

The diagnosis of constrictive pericarditis remains a challenge because its physical findings and hemodynamics mimic restrictive cardiomyopathy. Various diagnostic advances over the years enable us to differentiate between these two conditions. This review begins with a case report of constrictive pericarditis, followed by a brief history and discussions of etiologies. Clinical features, radiologic, electrocardiographic, angiographic findings, and hemodynamics of constrictive pericarditis are reviewed. The echocardiographic findings are detailed and the recent advances in Doppler flow velocity patterns of pulmonary, mitral, tricuspid valves and hepatic veins are reported. Nuclear ventriculograms depict rapid ventricular filling in constrictive pericarditis and differentiate it from restrictive cardiomyopathy. Endomyocardial biopsy helps further in recognizing the various types of restrictive cardiomyopathies. Computed tomography and magnetic resonance imaging delineate abnormal pericardial thickness in constrictive pericarditis. Association of characteristic hemodynamic changes and abnormal pericardial thickness > 3 mm usually confirms the diagnosis of constrictive pericarditis. Effusive and occult varieties of constrictive pericarditis are briefly described. This review concludes with emphasizing the importance of pericardial resection.

Adult↗
PubMed1999

Frey's syndrome after carotid endarterectomy.

Frey's syndrome after carotid endarterectomy (CEA) is due to iatrogenic injury to the auriculotemporal nerve and has not been previously reported. One month after uncomplicated CEA, our patient noted an erythematous flush and copious drainage of clear fluid from the superior portion of his neck wound whenever he ate, or smelled or thought of food. These symptoms lasted for 2 months and eventually resolved without intervention. The cause and treatment of Frey's syndrome is also described.

Aged↗
PubMed1999

Tomotherapy.

Tomotherapy is delivery of intensity-modulated, rotational radiation therapy using a fan-beam delivery. The NOMOS (Sewickley, PA) Peacock system is an example of sequential (or serial) tomotherapy that uses a fast-moving, actuator-driven multileaf collimator attached to a conventional C-arm gantry to modulate the beam intensity. In helical tomotherapy, the patient is continuously translated through a ring gantry as the fan beam rotates. The beam delivery geometry is similar to that of helical computed tomography (CT) and requires the use of slip rings to transmit power and data. A ring gantry provides a stable and accurate platform to perform tomographic verification using an unmodulated megavoltage beam. Moreover, megavoltage tomograms have adequate tissue contrast and resolution to provide setup verification. Assuming only translational and rotational offset errors, it is also possible to determine the offsets directly from tomographic projections, avoiding the time-consuming image reconstruction operation. The offsets can be used to modify the leaf delivery pattern to match the beam to the patient's anatomy on each day of a course of treatment. If tomographic representations of the patient are generated, this information can also be used to perform dose reconstruction. In this way, the actual dose distribution delivered can be superimposed onto the tomographic representation of the patient obtained at the time of treatment. The results can be compared with the planned isodose on the planning CT. This comparison may be used as an accurate basis for adaptive radiotherapy whereby the optimized delivery is modified before subsequent fractions. The verification afforded tomotherapy allows more precise conformal therapy. It also enables conformal avoidance radiotherapy, the complement to conformal therapy, for cases in which the tumor volume is ill-defined, but the locations of sensitive structures are adequately determined. A clinical tomotherapy unit is under construction at the University of Wisconsin.

Dose Fractionation, Radiation↗