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Biomedical subjects

Boban Thomas

Publications and source records attributed to Boban Thomas.

At least 19 recordsLinked to original sources

Ethnic differences in preoperative function of patients undergoing total knee arthroplasty.

The prevalence of osteoarthritis is high in all ethnic and demographic groups. The timing of surgery is important because poor preoperative functional status is related to poor postoperative function. The aim of our study was to compare the preoperative knee function in patients of Asian origin with that of Caucasians living in the same community. We carried out a prospective study of 63 consecutive Asian patients and 63 age- and gender-matched Caucasian patients undergoing total knee arthroplasty. Preoperative Knee Society Clinical Rating System scores were recorded as a separate knee score and knee function score. The mean preoperative knee score in Asian patients was 37.6 compared with 41.5 in Caucasians (p<0.12); this difference was not statistically significant. The mean preoperative knee function score in Asian patients was 32.5 compared with 45.0 in Caucasians (p<0.00015); this difference was highly statistically significant. We conclude that patients of Asian origin undergoing total knee arthroplasty have lower preoperative knee function than Caucasians do. Cultural beliefs and social support partially explain this discrepancy, but health care providers must attempt to educate patients and close family members about the importance of timing the surgery to obtain the optimum benefits of pain relief and function.

Aged↗

Effect of intra-articular steroids on deep infections following total knee arthroplasty.

Intra-articular steroids have been commonly used for the treatment of arthritis. The aim of our study was to discover any relation between deep infections following total knee arthroplasty and intra-articular steroid use before the arthroplasty. We undertook a retrospective matched cohort study. In the study group there were 32 patients with confirmed deep infection following total knee replacement. The control group consisted of 32 patients with no evidence of infection in the knee. There was no significant difference between the numbers of patients who received intra-articular steroid injection between the groups (P=1). We believe that infection following total knee replacement is due to multiple factors and that the use of intra-articular steroids does not alter the incidence of deep infections following total knee arthroplasty.

Aged↗

The potential role of cardiac magnetic resonance imaging in selecting patients with ischemic left ventricular dysfunction for the implantation of a cardioverter-defibrillator.

OBJECTIVES: To develop a protocol to risk stratify patients before ICD implantation in ischemic left ventricular dysfunction using magnetic resonance imaging and a gadolinium-based contrast agent. Ejection fraction as determined by other methods was reconfirmed using cardiac MRI. METHODS: Five patients considered for implantation of an ICD were prospectively offered a cardiac MR exam between Novem-ber 2003 and June 2004. All had a history of MI and LV dysfunction, had undergone complete coronary revascularization or were considered ineligible for revascularization. RESULTS: In three patients the MR ejection fractions were less than 30%, confirming the values detected by echocardiography. One patient had a larger EF by MRI compared to echo and ICD implantation was deferred. One patient thought to have an EF greater than 35% by echo on three studies was confirmed to have a much lower EF by MRI and was selected to undergo ICD implantation. CONCLUSION: Cardiac MRI can be used to further stratify patients selected for an ICD. Ejection fraction can be more reliably estimated by MRI and the presence of extensive scar can be detected. The presence of extensive scar and a low ejection fraction, which are two factors known to predispose patients to sudden cardiac death in ischemic left ventricular dysfunction, can be studied reliably by MRI.

Algorithms↗

The complementary role of cardiac magnetic resonance imaging in the evaluation of patients with aortic stenosis.

OBJECTIVE: To compare direct planimetry of aortic valve area (AVA) by cardiac magnetic resonance (CMR) imaging with transthoracic echocardiography (TTE), using the continuity equation. METHODS: 15 symptomatic patients with aortic stenosis were studied. AVA was measured with CMR from steady state free precession imaging by planimetry. AVA was also calculated by TTE images using the continuity equation. RESULTS: The evaluation of AVA by both CMR and TTE was possible in twelve out of fifteen patients. CMR was able to determine the AVA in all fifteen patients. AVAs obtained by CMR and TTE were very similar and a good correlation existed between the values obtained by either technique. CONCLUSION: CMR planimetry is highly reliable and reproducible. AVAs obtained by CMR compare well with those obtained by TTE. Therefore, CMR planimetry of AVA with steady state free precession is a useful diagnostic tool, particularly if uncertainty exists.

Aortic Valve Stenosis↗

Magnetic resonance imaging in patients with pacemakers--possible or taboo?

The presence of a pacemaker or an implantable cardioverter-defibrillator was considered an absolute contraindication for a magnetic resonance imaging study until recently. The publication of numerous studies, albeit with small numbers of patients, has challenged this assumption. With no serious adverse effects detected, it is evident that more patients with these devices will undergo an MR study. While we feel that no patient with an implanted device should be denied a potentially beneficial exam, some caution is obviously prudent and planning the study will enhance the benefit that the patient will derive while minimizing the risks.

Contraindications↗

Double orifice mitral valve in an asymptomatic adult with an unusual combination of congenital malformations: a case report.

We report a case of an asymptomatic adult patient, with several congenital malformations including an infrequent variant of double orifice mitral valve, postductal aortic coarctation, bicuspid aortic valve and an aneurysm of the right Valsalva sinus. The loss of support of the right coronary cusp of the aortic valve caused major aortic regurgitation. With the exception of the mitral valve, which was left untouched because it was neither stenotic nor regurgitant, all the other abnormalities were successfully corrected, in a two-step surgical approach.

Abnormalities, Multiple↗

PAMI risk score for mortality prediction in acute myocardial indarction treated with primary angioplasty.

OBJECTIVE: Based on the PAMI 1 and 2, AIR PAMI, and STENT PAMI trials, a risk score to predict mortality in patients undergoing primary angioplasty was recently proposed--the PAMI risk score. It includes only 6 parameters. As one of the first tools available to predict mortality in this group of patients, it results from controlled trials, with restricted inclusion criteria. It was our objective to evaluate how the PAMI risk score applies to "real world" patients. METHODS: 149 patients (mean age 58.2 +/- 13.6 years, 113 male) undergoing primary angioplasty were included. The PAMI risk score was applied and the patients were divided in 3 groups: 0 to 2 points (group A), 3 to 6 points (group B) and > or =7 points (group C). RESULTS: Sixty-eight patients (46%) were included in group A, 41 (27%) in group B and 40 (27%) in group C. There were no significant differences in pain-to-balloon times between the 3 groups. Immediate mortality (0%, 2.4% and 15%: p = 0.001), in-hospital mortality (2.9%, 7.3% and 37.5%; p < 0.001), 30-day mortality (2.9%, 7.3% and 37.5%; p < 0.001) and 6-month mortality (4.4%, 14.6% and 45%; p < 0.001) were significantly different between the 3 groups. CONCLUSIONS: The PAMI risk score is a simple prognostic tool, with parameters that can be easily acquired, enabling reliable prediction of immediate, in-hospital, 30-day and 6-month mortality in patients with acute myocardial infarction treated with primary angioplasty.

Adult↗

Magnetic resonance imaging of myocardial infarction using gadolinium-based contrast agent.

OBJECTIVES: To evaluate myocardial infarcts using a segmented inversion-recovery prepared gradient echo sequence on a 1.5 Tesla MR scanner after injection of a gadolinium-based contrast agent. METHODS: Fourteen patients were prospectively offered a cardiac MR exam between November 2003 and February 2004. Six patients had a history of anterior wall MI, six had a history of inferior wall MI and two patients had MI of undetermined location. RESULTS: Delayed enhancement indicating the presence of scarring was visualized in all fourteen patients. The scarring was transmural in ten patients and non-transmural in four patients. CONCLUSION: Delayed enhancement of infarcted areas in the myocardium after injection of gadolinium-based contrast agent represents scarring and adequate resolution exists to distinguish transmural from non-transmural scarring. This technique is useful in determining viability of infarcted myocardium, may detect infarcts missed by SPECT and may help in the selection of patients for implantation of defibrillators.

Contrast Media↗

A protocol to evaluate myocardial viability in ischemic left ventricular dysfunction using magnetic resonance imaging and a gadolinium-based contrast agent.

OBJECTIVES: A protocol to evaluate myocardial viability in ischemic left ventricular dysfunction using magnetic resonance imaging and a gadolinium-based contrast agent. METHODS: Twenty-two patients were prospectively offered a cardiac MR exam between November 2003 and June 2004. Twelve had a history of anterior wall MI, eight had a history of inferior wall MI and two patients had MI of undetermined location. Eight patients had left ventricular dysfunction. RESULTS: No patient with transmural scarring extending through more than 75% of the wall recovered normal wall motion despite revascularization when evaluated fourteen months later. Of the other three with scarring extending to less than 75% there was recovery in two patients. CONCLUSION: Viability assessment by cardiac MR using gadolinium contrast is a robust technique. No segment with >75% transmural enhancement (TE) recovers despite revascularization, while all segments with <25% TE recover contractility. Between these two extremes, methods other than extent of TE may have to be used, particularly low-dose dobutamine stress testing or evaluation of percentage of hyperenhanced area compared to the normal area in each segment.

Clinical Protocols↗

Three-dimensional contrast-enhanced magnetic resonance pulmonary angiography in the study of pulmonary vascular pathology.

OBJECTIVES: To assess the feasibility of performing pulmonary angiography using MRI with contrast enhancement in patients with pulmonary vascular disease. METHODS: We present our experience in ten individuals, two controls and eight patients who underwent the exam after injection of a gadolinium-based contrast agent on a 1 Tesla MR scanner using a time-of-flight sequence and breath-holding during injection of contrast. RESULTS: Pathology in the main pulmonary artery and its major branches was detected easily while resolution at the segmental and subsegmental levels was inadequate. CONCLUSION: Contrast-enhanced magnetic resonance pulmonary angiography is feasible on a 1 Tesla MR scanner for the study of pathology of the main pulmonary artery and its major branches, like massive pulmonary embolism. However its ability to detect and define distal vessel pathology as found in chronic thromboembolic pulmonary hypertension and small pulmonary emboli is limited.

Contrast Media↗

Simultaneous catheterization of the coronary arteries in the treatment of chronic total occlusions.

Chronic total occlusions present technical challenges to the interventional cardiologist, and are accompanied by an increased propensity for complications. We present an argument for the routine use of simultaneous bilateral coronary angiography to help define the lesion and optimize the therapeutic approach. Eight selected cases of CTO were revascularized using this technique resulting in immediate procedural success, devoid of complications, in all cases.

Adult↗

Inter-hospital transfer of critically-ill patients for urgent cardiac surgery after placement of an intra-aortic balloon pump.

METHODS: To assess the safety and feasibility of transfer of patients requiring urgent cardiac surgery, from a hospital without onsite cardiac surgical facilities, after insertion of an intra-aortic balloon pump (IABP) to maintain clinical and hemodynamic stability, a retrospective review of all cardiac charactheterizations was performed. Sixty-two patients required IABPs, among whom 24 were transported to a surgical center from the outskirts of Lisbon to the city center in an ambulance accompanied by a physician, a nurse and paramedical personnel. RESULTS: Patients who required hemodynamic support with IABPs usually had unstable angina with critical coronary lesions requiring immediate surgical intervention, hypotensive patients with mechanical complications after an AMI, and patients with AMI who did not receive thrombolytic therapy, and with coronary lesions not amenable to percutaneous coronary intervention. All patients reached the surgical center alive, and no patient had either hemodynamic or electrical instability during transport. CONCLUSIONS: Surface transport of patients requiring emergency cardiac surgery after insertion of IABPs is safe, feasible and may provide circulatory and clinical stability in a subset of critically-ill patients.

Adult↗