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Biomedical subjects

John M Alvarez

Publications and source records attributed to John M Alvarez.

11 recordsLinked to original sources
PubMed2005

Coronary bypass surgery for patients with chronic poor preoperative left ventricular function (EF<30%): 5-year follow-up.

BACKGROUND: Optimal therapy for patients with coronary artery disease and chronic poor left ventricular function, given the absence of randomized trials, is unclear. Although coronary surgery has been performed in such patients for 25 years, it is perceived as high risk and unproven long-term benefit, especially if thallium scanning fails to demonstrate large areas of viability. We report the results of coronary surgery in these patients. METHODS: Retrospective analysis by a standardized patient questionnaire, of 107 such consecutive patients offered coronary surgery. RESULTS: Mean follow-up was 3.3 years (range, 0.5-5.5); average patient age was 64.4+/-1 years. Preoperative thallium scans were performed solely on 31 patients with none or mild angina, of which 10 (32%) demonstrated large areas of viable myocardium. Perioperative mortality was 1.9%. On multivariate analysis, factors predictive of increased perioperative death were recent myocardial infarction (p<0.001) and nonelective surgery (p<0.001). Kaplan-Meier 5-year survival and freedom from major adverse cardiac events were 72.3 and 82.3%, respectively. In 21 patients, with preoperative nil-to-mild angina and nil-to-small areas of myocardial viability, thallium scanning failed to predict a successful outcome. CONCLUSION: Offering coronary surgery to these patients irrespective of thallium testing is safe and effective in the medium term. Early surgery is recommended.

Adult↗
PubMed2004

Current chemotherapeutic treatment of malignant pleural mesothelioma.

Malignant pleural mesothelioma is an aggressive malignancy which is almost always fatal; median survival is usually < 1 year. Most patients present with symptoms including pain, dyspnoea, pleural effusions and chest wall masses. Until recently, there has been no effective treatment which can improve symptoms and prolong survival. This article reviews recent developments in the treatment of mesothelioma, particularly advances in drug therapy and the use of the current most active drug combination: pemetrexed and cisplatin. Pemetrexed is a novel antifolate drug with multiple enzyme targets. The combination of pemetrexed and cisplatin demonstrated a survival advantage over cisplatin alone in patients with pleural mesothelioma, and can give symptomatic benefits. This combination has become the standard of care in mesothelioma treatment.

Antineoplastic Agents↗
PubMed2004

Avoidance of bleeding during surgery in patients receiving anticoagulant and/or antiplatelet therapy: pharmacokinetic and pharmacodynamic considerations.

Perioperative management of chronically anticoagulated patients and/or patients treated with antiplatelet therapy is a complex medical problem. This review considers the pharmacokinetic and pharmacodynamic properties of commonly used antiplatelet and anticoagulant drugs with special emphasis on loss of effects after discontinuation and possible counteracting (or antidote) strategies. These drugs are aspirin (acetylsalicylic acid), ticlopidine/clopidogrel, abciximab, tirofiban and eptifibatide, heparin (unfractionated and low-molecular-weight), warfarin and direct thrombin inhibitors. Since the pharmacological mechanisms of some of these drugs are based on irreversible or slowly reversible effects, their pharmacokinetic profiles are not necessarily predictive for their pharmacodynamic profiles. A close and direct relationship between plasma concentrations and effects is seen only for the glycoprotein (GP) IIb/IIIa inhibitors tirofiban and eptifibatide with a fast off-rate for dissociation from the GPIIb/IIIa receptor, and for direct thrombin inhibitors (hirudin and argatroban). For other compounds, drug concentrations in plasma and pharmacodynamic effects are not closely correlated because of, for example, irreversible binding to their target (aspirin, clopidogrel and abciximab), inhibition of the generation of a subset of clotting factors with differing regeneration and degradation rates (coumarins) or sustained binding to the vascular wall (heparins). Surgery in patients on anticoagulant and/or antiplatelet therapy may be categorised as: (i) elective versus urgent; and (ii) cardiopulmonary bypass (CPB) versus non-CPB. Monotherapy with clopidogrel or aspirin need not be discontinued in elective non-CPB surgery, and temporary discontinuation of warfarin should be accompanied by preoperative intravenous heparin only in selected high-risk patients. Vitamin K as an antidote for warfarin should only be used subcutaneously and solely in urgent/emergency surgery. In elective surgery requiring CPB (coronary artery bypass grafting), it is recommended to discontinue aspirin 7 days preoperatively in patients with a low risk profile. Patients requiring urgent CPB surgery (e.g. after failure of a percutaneous coronary angioplasty with or without coronary stent deployment) are usually pretreated with several antiplatelet agents (e.g. aspirin and clopidogrel, together with a GPIIb/IIIa inhibitor) together with unfractionated or low-molecular-weight heparin. With judicious planning, urgent/emergency cardiac surgery can be safely performed on these patients. Delaying surgery (e.g. for 12 hours in patients treated with abciximab) should be considered if possible. Standard heparin doses should be given to achieve optimal anticoagulation for CPB. Prophylactic use of aprotinin (intra- and/or postoperatively), aminocaproic acid or tranexamic acid should be considered. Early (in the operating theatre prior to chest closure) and judicious use of replacement blood products (platelets) should be commenced when clinically indicated.

Anticoagulants↗
PubMed2003

Atrial myxoma with coexistent coronary artery disease: a report of two cases.

The age at presentation and the symptoms of atrial myxomas and coronary artery disease can be similar. At times, the two lesions coexist. Operative strategy needs to be carefully planned when combined surgical treatment is contemplated. In the present paper, two cases of concomitant atrial myxoma and atherosclerotic coronary artery disease are reported. The first patient had a left atrial myxoma with triple-vessel coronary artery disease. The other had a right atrial myxoma and needed two bypass grafts. Both patients had a satisfactory outcome.

Journal Article↗
PubMed2003

Five year clinical follow up of patients who have had off pump coronary artery bypass grafting.

BACKGROUND: Off pump coronary artery bypass (OPCAB) has become a common technique for conducting coronary artery surgery. There has been some concern that the anastomoses might not be conducted as effectively on the beating heart, which could lead to poor long-term results. The aim of the present study was to follow up all patients who had undergone OPCAB at our institution to determine clinical outcomes up to 5 years postoperatively. METHODS: All living patients who had undergone OPCAB up until December 2000 were telephoned. For those who could be contacted, a detailed questionnaire was completed and the data were analysed. RESULTS: The technique of OPCAB was carried out on 312 patients. Thirteen of these patients died, five perioperatively. Actuarial survival at 5 years was 94.6% and freedom from cardiac related events was 92.1%. There were only two patients with angina worse than class I. Patients showed a high rate of compliance with risk factor management. Forty per cent of patients claimed to have had psychological problems related to the surgery. CONCLUSIONS: Mid-term results of OPCAB are very satisfactory, but randomised trials are needed to see whether they are different from the results of conventional coronary artery bypass grafting.

Journal Article↗
PubMed2003

Cardiac surgery in Australian octogenarians: 1996-2001.

BACKGROUND: The number of octogenarians receiving cardiac surgery is increasing. Concerns regarding the outcomes and significant expense required to provide this service have not been addressed because no prospective medium term outcomes of Australian octogenarians have been published. METHODS: Prospective analysis was undertaken of octogenarians having cardiac surgery from 1996 to 2001 in three hospitals of moderate case volume (400 patients per year) by: in-hospital audit and data acquisition, 1-year direct patient follow up in rooms, and a final follow up in late 2001 directly with the patient either in rooms or via telephone questionnaire. RESULTS: Sixty-four patients had cardiac surgery. All patients were severely disabled by symptoms (CCVS: III-IV, NYHA: III-IV) preoperatively, 14% were advised not to proceed with a surgical option but did so. Total operative in-hospital mortality was 6.3% (elective: 0%, urgent: 10.5%, P = 0.05), major complications were few 10.9% (seven patients; stroke: 1.6%, deep sternal infection: 1.6%, myocardial infarction: 1.6%, reoperation: 4.8%). At 1 year, despite 95% being free of significant cardiovascular symptoms (CCVS/NYHA: I-II), nearly one in five (19%) would not have proceeded with the surgery. However, at the final follow up (mean time: 2.8 years), freedom from cardiovascular symptoms remained high (95%), 94% remained independent and their quality of life was significantly better than before surgery. Although 59% suffered worsening of additional medical conditions, these conditions had a minor impact on their quality of life. Ninety-eight per cent would recommend cardiac surgery. Actuarial survival for all patients and for hospital survivors at 4 years was 67.9 +/- 4.1% and 74.2 +/- 4%, respectively. CONCLUSION: Medium-term follow up of Australian octogenarians who were offered cardiac surgery revealed that 94% remain independent and with an excellent quality of life. Age alone must not be a barrier to access to cardiac surgery.

Aged↗
PubMed2002

First-line treatment of deep sternal infection by a plastic surgical approach: superior results compared with conventional cardiac surgical orthodoxy.

A majority of cardiac surgeons manage deep sternal infection with sternal wound debridement, rewiring, and closed drainage, with or without antibiotic saline tube irrigation (the traditional approach). The authors' experience with the traditional approach was unsatisfactory; therefore, they undertook a radical change in management: an immediate plastic surgical approach. Hence, deep sternal infection was managed by immediate debridement followed by a bilateral pectoralis major myocutaneous advancement flap with greater omental transposition (PMOFR). This is the first such study reporting the effect of this strategy on the rate of eradication of deep sternal infection, intensive care unit stay, total hospital length of stay, major complications, mortality, intermediate survival, and patient satisfaction, as compared with the traditional approach used by cardiac surgeons at the authors' institution. All patients who developed a deep sternal infection from 1993 through 1998 at a tertiary teaching hospital were included. In the PMOFR group (nine patients), after a diagnosis of clinical sternal wound infection, debridement was performed immediately, either if sternal dehiscence occurred or in the absence of clinical dehiscence, if the patient or the sternotomy wound did not clinically improve with medical therapy within 48 hours from suspected diagnosis. Open irrigation and packing for 2 to 4 days was followed by treatment with a PMOFR. In the group treated using the traditional approach (12 patients), no predetermined plan was present. Thus, at the cardiac surgeon's discretion, wound debridement was undertaken, followed by closed drainage (three patients), closed tube irrigation (six patients), and open granulation with delayed plastic surgery (three patients). The incidence of major complications (PMOFR, 22 percent; traditional approach, 92 percent; p = 0.001), intensive care unit readmission (PMOFR, 0 percent; traditional approach, 58 percent; p = 0.005), total hospital length of stay (PMOFR, 32 days; traditional approach, 79 days; p = 0.001), reoperation rates (PMOFR, 0 percent; traditional approach, 100 percent; p = 0.001) and in-hospital 30-day mortality rate (PMOFR, 0 percent; traditional approach, 33 percent; p = 0.05) were superior in the PMOFR group. At a mean follow-up of 2 years, freedom from recurrence of the infection (PMOFR, 100 percent; traditional approach, 11.5 percent; p = 0.005) and overall survival rate (PMOFR, 100 percent; traditional approach, 50 percent; p = 0.005) were also superior with PMOFR. A majority of patients in the PMOFR group (90 percent) had no functional or cosmetic complaints secondary to the procedure.A predetermined plan of immediate debridement followed by treatment with PMOFR rapidly, reliably, and effectively eradicated deep sternal infection. This translated to reduced length of stay and need for additional surgery, improved survival, and excellent intermediate freedom from deep sternal infection, with minimal patient dissatisfaction. The traditional approach to managing deep sternal infection was thus abandoned.

Aged↗