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Biomedical subjects

J H Bett

Publications and source records attributed to J H Bett.

At least 19 recordsLinked to original sources
PubMed1998

Angiographic follow-up and clinical experience with the flexible Tantalum Cordis stent.

The Cordis stent is a flexible, highly radioopaque intracoronary stent engineered from a single Tantalum filament folded into a sinusoidal helical coil. It is premounted on a semicompliant balloon expandable stent delivery system. From September 1995-March 1996, 147 Cordis stents were deployed in 105 patients (aged 58+/-12 yr, 71% male). Clinical indications for stenting were unstable angina in 59 (55%), stable angina in 41 (38%), and acute myocardial infarction in 7 (7%). The target vessel was the right coronary artery in 45%, the left anterior descending in 31%, and the circumflex artery in 22%. One stent was deployed in a vein graft, and one stent was deployed in a left internal mammary artery graft. Stent deployment was achieved in all but one patient. Acute in-stent thrombosis occurred in 3 patients (2.9%). Two of these patients required urgent coronary artery bypass surgery. Subacute stent thrombosis occurred in 2 patients (1.9%). Minimum lumen diameter increased from 0.70+/-0.41 mm to 3.50+/-0.60 mm following stent placement. All patients received aspirin. Eighty-one patients (77%) received ticlopidine, and 4 patients (4%) received warfarin therapy. The mean hospital stay was 3.4+/-2.3 days. Six-month follow-up angiography was performed on 50 out of 55 eligible patients at one of the two institutions involved in this study. Computer-assisted quantitative coronary angiography defined a restenosis rate of 26%. Repeat revascularization was required in 8 patients (14.5%) at 6-mo follow-up. The Tantalum Cordis intracoronary stent is an effective and safe means of treating coronary lesions, even in patients with unstable ischemic syndromes. Acute and subacute rates of in-stent thrombosis were acceptable, and the long-term angiographic restenosis rates and need for repeat revascularization were favorable.

Angina Pectoris↗
PubMed1997

Multiple stent implantation in single coronary arteries: acute results and six-month angiographic follow-up.

A total of 147 stents were implanted (in overlapping manner in 76% of vessels) in a single coronary artery in 59 patients (60 vessels, 97 lesions, 2.45 stents/vessel) over a period of 18 mo using high pressure stent deployment without ultrasound guidance. The indications for stenting were suboptimal percutaneous transluminal coronary angioplasty (PTCA) result (45%), primary prevention of restenosis (44%), acute closure (10%), and restenosis after plain balloon angioplasty (1%). One patient required emergency coronary artery bypass grafting (CABG) (extensive dissection), and one required early intervention with plain balloon angioplasty and intracoronary urokinase for stent thrombosis. There were no deaths. Thirteen patients had recurrence of angina within 6 mo and angiograms were performed in all. These showed intrastent restenosis in nine (all had successful repeat plain balloon angioplasty), development of new disease in other vessels along with restenosis close to the stent in the target vessel in one (underwent elective CABG) and normal angiograms with widely patent stents in three. Forty-five patients (77%) remained free of recurrent angina and 25 of these had follow-up angiograms (56%) at a mean of 172 days, two showing restenosis. Thus, the restenosis rate per patient in the symptomatic group (angiographic follow-up in 100%) was 77% and in the asymptomatic group (angiographic follow-up in 56%) was 8%. The restenosis rate in the subgroup with bailout stenting (n = 6) was 20% (angiographic follow-up in 83%). The overall restenosis rate per patient was 32% (overall angiographic follow-up in 66%). During the 6-mo follow-up period, one patient underwent elective CABG (1.7%), one sustained a non-Q myocardial infarction (1.7%), nine had repeat PTCA to the target vessel (15.5%), and there were no deaths. The event-free survival rate was 77%. Multiple stent implantation aided by high pressure stent deployment without ultrasound guidance and with adjunctive optimal antiplatelet therapy without oral anticoagulation seems to be a useful and effective revascularisation strategy to deal with long lesions and acute dissections with a high procedural success rate. The restenosis rate is acceptable and is not appreciably high as reported in previous studies from the "warfarin era."

Adult↗
PubMed1997

Growth factors released into the coronary circulation after vascular injury promote proliferation of human vascular smooth muscle cells in culture.

OBJECTIVES: This study sought to 1) assess in vivo release of platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) into the coronary circulation after vascular injury in human subjects; and 2) evaluate mitogenic effects of PDGF and bFGF on the patient's own vascular smooth muscle cells (VSMCs). BACKGROUND: Circumstantial evidence suggests involvement of PDGF and bFGF peptides in the neointimal response to vascular injury. To date, no study has shown biologically active growth factors within the coronary circulation after vascular injury in human subjects. METHODS: In 18 patients, plasma PDGF AB, platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG) levels were measured in coronary sinus blood obtained before and up to 30 min after angioplasty. In five patients undergoing atherectomy, coronary sinus serum was added to cultured VSMCs derived from atherectomy tissue to assess the mitogenic potential of the serum. Mitogenicity attributable to PDGF and bFGF was determined using neutralizing antibodies to these factors. PDGF A, PDGF B and bFGF were localized within the atherectomy tissue using immunocytochemical analysis. RESULTS: Before angioplasty, PDGF AB, PF4 and beta-TG levels were elevated threefold in patients scheduled for angioplasty compared with those in control patients (p < 0.01). Within 5 min of angioplasty, PDGF AB levels increased twofold and returned toward preangioplasty levels at 30 min; PF4 and beta-TG levels remained elevated. Serum obtained at 30 min after atherectomy showed a sixfold increase in mitogenicity compared with preatherectomy serum (p = 0.01). This increase in mitogenicity was reduced by 20%, 40% and 65% in the presence of neutralizing antibodies to PDGF, bFGF and PDGF + bFGF, respectively. PDGF A, PDGF B and bFGF were visualized within the intima of the atherectomy tissue. CONCLUSIONS: The change in plasma PDGF level is consistent with first-phase release of PDGF after vascular injury. The increase in mitogenicity of serum suggests that PDGF and bFGF are biologically active.

Adult↗
PubMed1997

Interventional management of acute myocardial infarction (AMI).

The best way to limit infarct size and improve survival in patients with early heart attacks is to restore as quickly as possible patency in the infarct-related artery and blood flow to the threatened myocardium. The value of thrombolytic therapy and aspirin has been shown in large clinical trials. A regimen of accelerated recombinant tissue plasminogen activator is more effective than those using streptokinase. In older patients, there is a greater risk of haemorrhagic stroke; nevertheless, thrombolytic treatment saves more lives because the mortality of myocardial infarction (MI) is higher. Thrombolytic therapy fails to restore blood flow sufficiently rapidly or completely in nearly one-fifth of patients. Its efficacy, therefore, has been compared with immediate or direct angioplasty (PTCA). If it can be done promptly enough, PTCA is superior in preventing recurrent ischaemia and the combined outcome of death or non-fatal reinfarction, and is associated with a lesser risk of intracranial haemorrhage. It may also be cheaper because patients spend less time in hospital and fewer of them require late revascularisation. PTCA should be considered for patients with cardiogenic shock or for those in whom there is a contraindication to thrombolytic therapy. The benefits of prompt treatment have been reduced by excessive delay in reaching hospital and door-to-needle time. After fibrinolysis, coronary angiography and PTCA may be reserved for those with spontaneous angina or exercise-induced ischaemia.

Angioplasty, Balloon, Coronary↗
PubMed1996

Elective implantation of intracoronary stents without intravascular ultrasound guidance or subsequent warfarin.

Two hundred forty-three stents (203 Palmaz-Schatz, 40 Glanturco-Roubin) were electively Implanted in 188 lesions in 168 patients (mean age 58 +/- 10 years, 77% males) using angiographic but not ultrasound guidance. Patients were treated subsequently with aspirin and observed in hospital for up to 7 days. Those with acute myocardial infarction, radiolucent defects in coronary arteries suggestive of thrombus, and results that were not optimal after stent implantation were anticoagulated with warfarin and not Included in the study. Two had subacute stent thrombosis and two patients non-Q-wave myocardial infarction in-hospital. At follow-up (median 149 days) none had had subacute stent thrombosis, one suffered non-Q-wave myocardial infarction, none had died, and none had developed major complications at the vascular access site. Fourteen (8%) had undergone further revascularisation procedures. This initial experience suggests that aspirin is sufficient to prevent subacute stent thrombosis after elective high pressure assisted coronary stent implantation without intravascular ultrasound guidance if the angiographic appearance after stent deployment is optimal.

Adult↗
PubMed1994

The effect of oral anticoagulant therapy on APTT results from a bedside coagulation monitor.

OBJECTIVE: The Ciba Corning 512 coagulation monitor (CC512) can be used to monitor heparin therapy by performing an activated partial thromboplastin time (APTT) at the patient's bedside. This study was designed to compare the CC512 results to results using the laboratory system. The relative sensitivities of both systems to the effect of oral anticoagulant therapy also was investigated. METHODS: Activated partial thromboplastin times were performed with both the CC512 and laboratory system on 74 specimens from patients receiving i.v. heparin therapy, and on 14 specimens from patients on warfarin only. Heparin assays were performed on 43 of the specimens from the heparinized patients. RESULTS: When a patient was receiving heparin only, the APTT results of the CC512 proved to be similar to existing laboratory methods. The CC512 APTT results of patients on warfarin only were markedly prolonged, whereas the laboratory APTTs were only slightly affected. CONCLUSION: The CC512 results were comparable to the laboratory system. However, the CC512 APTT was more sensitive to the effect of warfarin than the laboratory APTT system used in this study. CC512 APTT results on a patient receiving both oral and intravenous anticoagulation could be misleading.

Administration, Oral↗
PubMed1994

Percutaneous transluminal coronary angioplasty: clinical and quality of life outcomes one year later.

BACKGROUND: The quality of life status of patients prior to and following percutaneous transluminal coronary angioplasty (PTCA) has not been comprehensively investigated. AIM: This study was carried out to determine the effect that PTCA has on patients' quality of life. METHODS: Data on 209 patients were collected one day pre-PTCA and at a mean of two and 11 months post-PTCA. Data on symptomatic status, functional capacity, life satisfaction and psychological well-being were analysed quantitatively. Clinical outcomes, patient perception of PTCA and employment status wee analysed by descriptive statistics. RESULTS: Highly significant improvement in all quality of life measures was found at the early follow-up (p < .001). This improvement was sustained at the late follow-up. At the late follow-up, 58% of patients felt that PTCA had been very beneficial to their health and well-being, and 79% of workers had returned to work. PTCA was primarily successful in 91% of vessels dilated. There were no procedural-related deaths, 12 patients (6%) developed acute occlusion and three patients (1.5%) experienced myocardial infarction (MI). A symptomatic restenosis rate of 16% was found, including 19 patients (9%) requiring repeat PTCA and 14 (7%) undergoing coronary artery bypass grafting (CABG). CONCLUSION: These findings suggest that, after PTCA, the majority of patients experienced improved quality of life which was sustained one year later.

Angioplasty, Balloon, Coronary↗
PubMed1993

LATE assessment of thrombolytic efficacy with alteplase (rt-PA) six-24 hours after onset of acute myocardial infarction.

Conflicting results on the benefit of thrombolytic therapy administered six to 24 hours after the onset of myocardial infarction (MI) led to the LATE trial. Five thousand seven hundred and eleven patients were treated with recombinant tissue plasminogen activator (t-PA) or placebo, treatment was begun between six and 24 hours after the onset of infarction. For patients treated within 12 hours, there was a relative reduction in 35 day mortality of 25%, but no benefit for those treated at 12 to 24 hours. The benefits were confined to those whose treatment was begun within three hours of admission to hospital. These results widen the window for effective treatment from six to 12 hours after the onset of infarction, but emphasise the need for expeditious treatment when the diagnosis of MI is suspected.

Double-Blind Method↗
PubMed1992

Clinical results and quality of life after percutaneous transluminal coronary angioplasty: a preliminary report.

To evaluate the effect of percutaneous transluminal coronary angioplasty (PTCA) on quality of life, data on symptomatic status, functional capacity, life satisfaction, and psychological wellness were collected on 102 patients at 1 day pre-PTCA and 2 months post-PTCA, and on the first 50 of these patients at 10 months post-PTCA. There were highly significant changes (p < 0.001) in all quality of life measures between pre-PTCA and the 1st follow-up measurements. No further significant changes occurred in these measures between the 1st and 2nd follow-up measurements, indicating that the initial improvement in quality of life was sustained over this period. Data on primary success rate, complications, and pre- and post-PTCA risk factor scores are also reported.

Adult↗
PubMed1989

Experience with a mobile coronary care unit in Brisbane.

We examined the performance of a hospital-based mobile coronary care unit staffed by emergency physicians, coronary care nurses, and ambulance personnel in a metropolitan setting (Brisbane, Australia). Our unit attended 2,260 calls during 18 months of operation. Standard dispatched ambulances arrived first to 78% of the 2,260 calls. Ten percent of these calls were to patients who had died or had arrested; 45% of these patients were found in ventricular fibrillation and 10% were discharged alive from the hospital. Survival was related to the performance of CPR before the arrival of the unit and to the finding of ventricular fibrillation. As the success of our unit was clearly inferior to that reported from centers where the first-responders are licensed to defibrillate, its operations have ceased and regular ambulance crews are being taught to recognize and treat patients with ventricular fibrillation.

Adolescent↗
PubMed1988

Brucellosis complicated by aortic valve endocarditis.

A 30 year old veterinary surgeon developed a febrile illness with serological evidence of Brucellosis. He was known to have aortic valve disease and during the course of the illness, the clinical features of endocarditis became evident, with a vegetation visible echocardiographically on the aortic valve. Because of persisting fever despite appropriate antibiotic therapy, aortic valve replacement with a viable cryopreserved allograft aortic valve was undertaken. Organisms consistent with Brucella species were demonstrated in the excised vegetation. The patient received a six week course of antibiotics and his post-operative course was uneventful.

Adult↗
PubMed1986

Successful total correction of Fallot's pentalogy in the seventh decade of life.

The patient described had correction of Fallot's pentalogy at the age of 61 and has been asymptomatic for a further five years. Survival with this disorder to this age is extremely rare, and successful surgery for cyanotic congenital heart disease in the seventh decade of life has apparently not been reported previously.

Age Factors↗
PubMed1985

Right heart thrombus: recognition, diagnosis and management.

The clinical, echocardiographic, hemodynamic, angiographic and pathologic features of five patients who had right heart thrombus are presented and their management is discussed. Two modes of presentation were recognized. In four patients, right heart thrombus complicated peripheral venous thrombosis and was associated with major pulmonary thromboembolism and right heart obstruction. In the fifth, it complicated myocarditis with heart failure and appeared to cause right heart obstruction. Two-dimensional echocardiography was diagnostic of right heart thrombus in four patients and showed evidence of right heart dysfunction in those with major pulmonary thromboembolism. The diagnosis was confirmed at surgery in three patients and at autopsy in one. Three patients successfully underwent surgical removal of the thrombus followed by anticoagulation. One patient was treated successfully with anticoagulation alone. The only death occurred in the patient with myocarditis.

Adolescent↗