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T J Spyt

Publications and source records attributed to T J Spyt.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intraoperative and laboratory evaluation of skeletonized versus pedicled internal thoracic artery.

BACKGROUND: The skeletonization of internal thoracic artery is postulated to improve graft length, early blood flow, sternal blood supply, and postoperative respiratory function. Concern exists that skeletonization may injure internal thoracic artery, precluding good results of surgery. Reports on endothelial function of skeletonized internal thoracic artery are lacking. METHODS: A prospective assessment of early clinical outcomes of 357 consecutive patients undergoing coronary artery bypass grafting was performed: 287 patients with nonskeletonized and 70 with skeletonized left internal thoracic artery (LITA). The lengths of LITA and of its discarded distal segment, as well as free LITA blood flow, were measured. The dose-effect relationship for relaxation to acetylcholine was studied in the organ bath. RESULTS: Apart from a higher incidence of breaching the pleura with nonskeletonized LITA the clinical outcomes were comparable. The length of skeletonized LITA was 17.8+/-1.14 cm versus 20.3+/-0.52 cm skeletonized (p = 0.11). The length of discarded LITA was shorter in nonskeletonized artery (0.8+/-0.28 cm versus 2.6+/-0.49 cm; p = 0.022). The free LITA blood flow was 66.3+/-7.42 mL/min in nonskeletonized vessel versus 100.3+/-14.84 mL/min in skeletonized (p = 0.048). The acetylcholine-induced relaxation was similar in both groups (maximal relaxation, 80.7%+/-5.95% in nonskeletonized versus 72.9%+/-9.11% in skeletonized; not significant; negative logarithm of half-maximal effect, 7.43+/-0.18 versus 7.1+/-0.10, respectively; p = 0.063). CONCLUSIONS: Skeletonization does not damage the endothelial function of the LITA. Higher free blood flow and available LITA length should encourage the use of skeletonized LITA in clinical practice.

Acetylcholine↗
PubMed1998

Preoperative and early postoperative assessment of the internal thoracic artery by transcutaneous duplex ultrasound in coronary artery bypass grafting.

We examined internal thoracic artery by transcutaneous duplex ultrasound in 26 patients on four occasions: 4 (+/-2) days before the operation, and 61 (+/-8) minutes, 5 days and 53 (+/-3) days postoperatively. There was dominant systolic flow in preoperative scans. After the operation a characteristic biphasic flow with increased peak diastolic velocity and a decrease in peak systolic/peak diastolic velocity ratio was detected in all patients. The pulsed Doppler spectrum was used to measure peak velocity, time averaged mean velocity and time averaged maximum velocity. Resting internal thoracic artery flows calculated using time averaged mean velocity were 30.9+/-5.4 ml/min preoperatively, 40.7+/-6.3 ml/min immediately after surgery, 41.1+/-8.2 ml/min at 5 days and 40.1+/-4.9 ml/min at 53 days. There were no significant changes in resting internal thoracic artery flow between early and late postoperative studies. Flow estimates calculated using 0.5 x time averaged maximum velocity or time averaged mean velocity showed good agreement. Early postoperative measurements appear to be a good predictor of later resting graft flow.

Aged↗
PubMed1998

Role of transcutaneous ultrasound in evaluation of graft patency following minimally invasive coronary surgery.

OBJECTIVE: Recent development in minimally invasive coronary surgery prompted us to carry out prospective evaluation of patients undergoing coronary artery bypass grafting through left anterior small thoracotomy. METHODS: Between April 1996 and February 1997, 15 patients (age 32-70, 12 male) were operated on. The left internal thoracic artery (LITA) basal flow was assessed by means of transcutaneous Duplex ultrasound scanning with pulsed waved Doppler. Eight patients were studied in the immediate postoperative period (2-4 days) and seven patients (1-7 months) following revascularisation. In addition to that, nine patients underwent coronary angiography. RESULTS: LITA graft flows were quantifiable in all 15 patients. In two patients there was a significant reduction in both time-averaged velocity and total flow. The subsequent coronary angiogram revealed severe (>50%) stenosis of LITA graft in both patients. One of these patients had a reversible obstruction documented by Duplex scanning and coronary angiography. Systolic measures did not differ between normal (13) and stenosed grafts (2), but diastolic time-averaged velocity (indicating coronary run-off) and total flow appeared lower in the latter. CONCLUSIONS: LITA flow following left anterior small thoracotomy surgery can be evaluated non-invasively. Measurement of diastolic flow (i.e. coronary perfusion rather than internal thoracic branch run-off) and total flow is useful in estimating graft function.

Adult↗
PubMed1997

Signal averaged P wave compared with standard electrocardiography or echocardiography for prediction of atrial fibrillation after coronary bypass grafting.

OBJECTIVE: To define the clinical value of the signal averaged P wave (SAPW) and to compare it with the standard electrocardiogram (ECG), echocardiogram, and clinical assessment for the prediction of atrial fibrillation after coronary bypass grafting (CABG). DESIGN: Prospective validation cohort study. SETTING: Regional cardiothoracic centre. PATIENTS: 201 unselected patients undergoing first elective CABG were recruited over six months. Patients requiring concomitant valve surgery were excluded. MAIN OUTCOME MEASURES: Age, sex, cardiothoracic ratio, and cardioactive drugs were noted. P wave specific SAPW recordings, ECG, and M mode echocardiograms from which left atrial diameter was measured were performed within 24 hours of surgery. Filtered P wave duration (SAPWD), spatial velocity, and energy were calculated from the SAPW. From the ECG, lead II P wave duration, P terminal force in lead V1, total P wave duration, and isoelectric interval were measured. Patients had Holter monitoring for 48 hours postoperatively and daily ECGs until discharge. RESULTS: Two patients died (1%) and 10 were unsuitable for analysis (5%). Of the remaining 189, 51 (27%) had atrial fibrillation (AF) lasting > 1 hour at a mean of 2 (0.5 to 7) days after CABG. Of the variables examined, only SAPWD (AF group 148 (SD 12), v 142 (14) ms, P = 0.008) and male sex (AF group 96%, v 78%, P < 0.01) were significantly different. A prospectively defined SAPWD of > 141 ms predicted atrial fibrillation with positive and negative predictive accuracies of 34% and 83%. Logistic regression analysis identified both male sex and SAPWD as significant independent predictors of postoperative atrial fibrillation. CONCLUSIONS: Signal averaged P wave duration was a better predictor of atrial fibrillation after coronary bypass grafting than standard electrocardiographic or echocardiographic criteria. The predictive value of this test is such that it is likely to be useful in the design of prospective trials of prophylactic antiarrhythmic treatment but is of limited use using current techniques in the clinical management of individual patients.

Atrial Fibrillation↗
PubMed1996

Randomized comparison of ultrasonic aspiration versus conventional electrocautery for dissection of the human internal thoracic artery.

The most common technique currently employed to harvest the internal thoracic artery for coronary artery bypass grafting is conventional electrocautery. This study compared an alternative method, electrocautery with an ultrasonic aspirator, for harvesting the internal thoracic artery. Patients were randomly assigned to one of six experimental groups (conventional electrocautery, ultrasonic aspirator at settings of 60%, 80%, and 100% power output, and ultrasonic aspirator in 100% CAVI-Pulse modes 1 and 3). Ring segments of internal thoracic artery were studied in an organ bath. Contraction responses were elicited with 123 mmol/L potassium physiologic salt solution, KPSS, KPSS solution containing noradrenaline, and a cumulative noradrenaline dose-contraction curve. Relaxation studies were performed with the vasodilators acetylcholine, bradykinin, and sodium nitroprusside. Forty percent of the electrocauterized vessels were traumatized or damaged and failed to respond to contractile stimuli, whereas only 10% of the vessels in ultrasonic aspirator groups 60%, 80%, and 100% failed to respond. All vessels in the group harvested by ultrasonic aspirator in 100% CAVI-Pulse mode 1 responded, whereas 20% of the vessels in the group harvested by ultrasonic aspirator in 100% CAVI-Pulse mode 3 failed to respond. All settings of electrocautery with an ultrasonic aspirator produced a greater contractile response to KPSS and noradrenaline. Acetylcholine and sodium nitroprusside produced similar relaxations in all groups, but the bradykinin responses were significantly improved in all groups undergoing 100% electrocautery with an ultrasonic aspirator. These results suggest that 100% electrocautery with an ultrasonic aspirator, particularly in 100% CAVI-Pulse mode 1, resulted in less damage and trauma than conventional electrocautery during harvesting of the internal thoracic artery.

Adult↗
PubMed1996

Bilateral and unilateral use of internal thoracic artery for myocardial revascularization. Comparison of extubation outcome and duration of hospital stay.

The left internal thoracic artery is usually used as arterial conduit for myocardial revascularization; however, there is an increasing popularity of bilateral use of this artery for grafting. We examined 180 patients with both types of arterial conduits to answer whether bilateral use of the internal thoracic artery makes the difference in postoperative extubation outcome and duration of hospital stay in comparison to the unilateral use of this conduit. Ninety-three patients with bilateral conduit and 87 patients with unilateral conduit, with comparable age, cardiopulmonary bypass, and aortic cross-clamp time have been studied. On the basis of statistical and retrospective analysis, we conclude that bilateral use of internal thoracic artery for myocardial revascularization prolongs required postoperative respiratory support (12.0 h against 7.6 h) not affecting the duration of the mean hospital stay.

Humans↗
PubMed1995

Management of lower limb ischaemia associated with the use of intra-aortic balloon pumps during cardiac surgery.

OBJECTIVE: To audit the lower limb vascular complications associated with the use of an intraaortic balloon pump (IABP) on a cardiothoracic unit over a 12 month period. DESIGN: Retrospective analysis. SETTING: Regional university cardiothoracic unit. PATIENTS: Fifty four IABPs inserted into 51 patients. RESULTS: Seventeen patients (33%) died from cardiogenic shock in the immediate postoperative period. Of the remaining 34 patients (37 IABPs), lower limb vascular complications occurred in nine patients (26%) who underwent 11 IABP insertions (30%). Vascular complications included groin haematomas (n = 2 insertions), compartment syndrome (n = 2 insertions), femoral artery trauma (n = 7 insertions). CONCLUSIONS: Prompt management by peripheral vascular surgeons resulted in limb salvage in 10 legs and only one death from a pulmonary embolus.

Acute Disease↗
PubMed1995

Video-thoracoscopic lung biopsy in diagnosis of interstitial lung disease.

Lung biopsy remains an important investigation in the diagnosis of diffuse interstitial lung disease despite improved diagnostic yield of high resolution computed tomography scanning. We describe 19 pulmonary wedge biopsies (13 men and 6 women) performed using videothoracoscopic technique. The median age of the patients was 56 years (range 32-72 years). All our patients were suspected to have diffuse interstitial lung disease and were referred for lung biopsy to obtain a histological diagnosis. Thoracoscopic wedge excisions were accomplished under general anaesthesia using high frequency jet ventilation and a percutaneous stapling device. A tissue diagnosis was obtained in all patients: 8 had cryptogenic fibrosing alveolitis, 3 had interstitial pulmonary fibrosis, 2 had emphysema, 2 had extrinsic allergic alveolitis, 2 had sarcoidosis, 1 had non-specific chronic inflammation, and 1 had pulmonary haemosiderosis. There were no operative deaths. There was one failure resulting in conversion to an open procedure. There were three complications: two air leaks and one effusion. Median postoperative hospital stay was 2 days (range 2-7 days). We conclude that videothoracoscopic wedge biopsy is a safe and effective procedure and should be recommended in patients who require a histological diagnosis of diffuse interstitial lung disease.

Adult↗
PubMed1994

Use of expandable wire stents for malignant airway obstruction.

The symptoms of progressive dyspnea and stridor in the setting of malignant airway obstruction are severe and distressing. Conservative nebulizer and oxygen therapy offer little relief, and conventional stenting with T tubes requires a tracheostomy. In this article, we describe our experience with stenting in the treatment of malignant mediastinal disease using the Gianturco expanding metal-wire stents. The technique of placement is simple and the procedure was successful in all 21 cases. Relief of stridor was immediate and the dyspnea usually abated. These benefits continued through the mean survival period after stenting of 134 days (range, 2 to 799 days). The patients required only brief hospitalization (2.83 days) before returning home or to the referring institution. It appears that expandable wire stents may offer a simple yet effective intervention in the palliative treatment of mediastinal malignancy.

Adult↗
PubMed1994

Transcutaneous ultrasound assessment of internal thoracic artery to coronary artery grafts in patients with and without ischaemic symptoms.

OBJECTIVE: To evaluate transcutaneous duplex ultrasound in the assessment of internal thoracic artery to coronary artery grafts. SETTING: Regional cardiothoracic centre. METHODS: Prospective duplex ultrasound evaluation of 83 consecutive patients undergoing left internal thoracic artery to coronary artery grafts, together with combined angiographic and duplex ultrasound evaluation of 17 patients with suspected recurrent myocardial ischaemia after internal thoracic artery grafting. RESULTS: The grafted internal thoracic artery was imaged in 65 (78%) of 83 consecutive postoperative patients, and in 13 (75%) of 17 patients with suspected graft dysfunction. Grafts were recognised by their characteristic position and biphasic blood flow pattern. Resting graft flow was estimated from the time averaged velocity and graft cross sectional area. Median resting flow in patients without ischaemic symptoms was 36 ml/min (interquartile range 24 to 49 ml/min). Of 13 patients with recurrent ischaemia in whom the graft could be imaged, nine patients with estimated flow in the lowest quartile or abnormal flow profiles, or both, had graft disease or anastomotic problems on angiography, while four with satisfactory graft flow on ultrasound examination had normal graft flow on angiography, but had evidence of native disease progression in other vessels. Two of four patients in whom it was not possible to image the graft on ultrasound had satisfactory graft function on angiography. CONCLUSIONS: For those patients whose internal thoracic artery graft can be imaged, transcutaneous duplex ultrasound is a helpful non-invasive guide to graft function. The main limitations to the technique are an inability to image the graft in about 20% of patients, and possible inaccuracy in estimating graft diameter.

Coronary Artery Bypass↗
PubMed1994

Clinical significance of heparin in the residual pump oxygenator blood, reinfused postoperatively after cardiopulmonary bypass.

Postcardiopulmonary bypass (CPB) heparin levels and thrombin time were measured in 20 patients following routine open cardiac operations. There was a statistically significant increase in heparin concentration and thrombin time ratio on completion of transfusion of the residual pump oxygenator blood. An hour after the end of the transfusion there was no statistically significant difference in the heparin concentration and thrombin time ratio compared to values before and immediately after transfusion. We also observed a significant decrease in the chest drainage over a period of four hours which was unrelated to plasma heparin level. Measurements of thrombin time in the post bypass period closely follow plasma heparin levels. If postoperative bleeding arose it was due to inadequate surgical haemostasis or coagulation defect other than residual heparinization. Thus this confirms further that heparin is not the sole aetiological factor in postoperative bleeding post-CPB.

Adult↗
PubMed1993

Early results of combined carotid endarterectomy and coronary artery bypass grafting in patients with severe coronary and carotid artery disease.

The management of patients with carotid artery disease who require coronary artery bypass grafting (CABG) remains controversial. Several published series from the USA (including one with prospective randomization) advocate a combined approach of carotid endarterectomy (CEA) followed immediately by coronary artery bypass surgery. However, experience of combined carotid endarterectomy and coronary bypass grafting has not been previously reported by a centre from the United Kingdom. Between 1986 and 1991 we performed this combined procedure on 18 patients who required myocardial revascularization and had co-existing severe (> 70%) carotid stenosis. Sixteen patients (89%) had angina and 11 patients (61%) had symptomatic carotid artery disease. The perioperative mortality was 5.5% and the ipsilateral perioperative stroke rate was 5.5%. These early results are encouraging and suggest that further evaluation of combined carotid endarterectomy and coronary artery bypass surgery is warranted.

Adult↗
PubMed1992

Transcutaneous ultrasound measurement of blood-flow in internal mammary artery to coronary artery grafts.

Transcutaneous doppler ultrasound was used to examine internal-mammary-artery (IMA) blood-flow in 26 patients with IMA coronary bypass grafts. The ungrafted right IMA could be seen in all of 19 patients, the grafted left IMA in 16 of 26, and the grafted right IMA in 3 of 7. The velocity profile recorded from the proximal part of the grafted IMA is distinct from that of an ungrafted artery, with a systolic peak which reflects graft capacitance in the face of high intramyocardial resistance, and a diastolic peak which represents graft conductance when intramyocardial resistance is low. Total graft blood-flow can be estimated from the mean velocity and the measured vessel diameter; resting flows ranged from 22 to 79 ml/min. In recently grafted patients, resting graft blood-flow correlated with myocardial "run-off" estimated from preoperative arteriograms; graft blood-flow increased appropriately with exercise. This simple, non-invasive technique to measure IMA graft blood-flow may find applications for routine postoperative follow-up of patients with IMA grafts and for studies on the physiology and pharmacology of coronary artery blood-flow.

Blood Flow Velocity↗