Malcolm J.R. Dalrymple-Hay

Ventricular thrombosis and systemic embolism in bodybuilders: etiology and management.

Increased thrombogenicity and acute embolism are well-recognized complications of chronic anabolic steroid abuse. The following cases highlight such dangers in steroid-enhanced bodybuilders who developed intracardiac thrombosis that subsequently embolized. Systemic anticoagulation and surgical thrombectomy constituted the mainstay treatment. This represents the first report of such devastating cardiovascular complications after anabolic steroid abuse and their management.

Postinfarction Ventricular Septal Rupture: The Wessex Experience

Surgical repair of a postinfarct ventricular septal defect (VSD) remains a difficult surgical challenge associated with a significant operative mortality. Between 1972 and 1995, 179 patients with a postinfarct VSD have undergone operation in this institution. There were 118 males and 61 females, with a mean age of 66 years (range 43 to 80). Operative mortality was 26.7%. Surgery was deferred until 1 month after the septal rupture in 29 patients, with these labeled as having a chronic VSD. The remaining 150 underwent operation on within 1 month of infarction and are described as having an acute VSD. For those with an acute VSD, factors significantly associated with an increased risk of 30-day mortality included preoperative New York Heart Association status (P = .04), site of myocardial infarction (inferior worse than anterior) (P = .004), cross-clamp time (P = .05) and cardiopulmonary bypass time (P = .0001) (logistic regression). On multiple logistic regression, only cardiopulmonary bypass time remained significant. Survival including in-hospital mortality at 5 and 10 years was 49% +/- 4% and 31% +/- 5% and excluding in-hospital mortality was 72% +/- 5% and 45% +/- 6%, respectively. Those patients who survived attained a good quality of life. No factors were significantly associated with prolonged survival.

Effects of positive end-expiratory pressure on transthoracic impedance--implications for defibrillation

The success of defibrillation is determined by trans-myocardial current. This current is inversely proportional to transthoracic impedance (TTI). We proposed that increasing lung volume using positive end-expiratory pressure (PEEP) would increase TTI. 12 healthy subjects aged 21-37 years (6 male) were recruited. TTI between self-adhesive defibrillation pads placed in the standard antero-apical position was measured at 30 kHz at end-expiration using Bodystat MultiScan 5000 equipment. PEEP at 2.5, 5.0, 10.0, 20.0 and 40.0 cm H2O was generated using a standard continuous positive airways pressure (CPAP) circuit. Data were analysed using linear regression and paired t-tests comparing baseline TTI with that at a given PEEP. Mean (+/- S.D.) baseline TTI was 65.7 +/- 6.9 omega. TTI increased linearly with increasing PEEP (r2 = 0.99; P < 0.001). Mean percentage increases in TTI were 0.6% at 2.5 cm H2O PEEP (P = 0.05), 1.5%, at 5.0 cm H2O PEEP (P < 0.001), 3.1% at 10.0 cm H2O PEEP (P < 0.001), 5.6% at 20.0 cm H2O PEEP (P < 0.001) and 10.4% at 40.0 cm H2O PEEP (P < 0.001). PEEP increases TTI, proportionately reducing transthoracic current during defibrillation. Clinically, high levels of PEEP (20-40 cm H2O) may occur during ventilation of patients at cardiac arrest and in acute asthmatics. To maximise peak defibrillation current, PEEP should either be minimised prior to defibrillation or consideration should be given to earlier use of high energy levels for defibrillation.

Should coronary artery bypass grafting be performed at the same time as repair of a post-infarct ventricular septal defect?

OBJECTIVE The value of coronary artery bypass grafting (CABG) at the time of repair of a post-infarct ventricular septal defect (VSD) remains controversial. The aim of this study was to analyse the effect of CABG on early mortality and survival following repair of an acquired VSD. METHODS Over 23 years, 179 patients, 118 male, 61 female, mean age 66 years (range 43-80), have undergone repair of a post-related VSD in our unit. A total of 29 patients, who predominantly form the earlier part of the series, were operated on greater than 1 month after the infarct and are, therefore, excluded. Coronary angiography was performed in 98 (65.3%) of the remaining 150 patients. Of these, 41 had coronary artery disease (CAD) limited to the infarct-related vessel and 57 had additional significant CAD. Those with CAD limited to the infarct-related vessel were not grafted (Group A). Of those, 40 with significant CAD underwent CABG at the time of VSD repair (Group B) and 17 did not (Group C). In 52 patients the coronary anatomy was not documented (Group D). Risk factors for early mortality were evaluated using logistic regression. Actuarial survival was compared using log rank and Wilcoxon tests. Coxs proportional hazards method was used to determine factors affecting survival. RESULTS Overall, 30 day mortality was 32%. CABG did not significantly decrease operative mortality (logistic regression). There was no statistically significant difference in early mortality or actuarial survival between the four groups. CABG was not associated with an increased survival (Coxs method). CONCLUSIONS Concomitant CABG at the time of VSD repair does not affect early mortality nor confer survival benefits. There seems to be no demonstrable benefit in revascularisation at the time of repair and, therefore, it may be unnecessary to perform CABG or coronary angiography in these patients.

A single-center experience with 1,378 CarboMedics mechanical valve implants

BACKGROUND The CarboMedics bileaflet prosthetic heart valve was introduced in 1986. We first implanted it in March 1991. The purpose of this study was to analyze our clinical experience with this valve. METHODS Between March 1991 and December 1997, 1,378 valves were implanted in 1,247 patients, 705 men (56.5%) and 542 (43.5%) women with a mean age of 62 +/- 11.9 years (+/- the standard deviation). Follow-up is 99% complete and totals 3,978 patient-years. RESULTS The early mortality rate was 4.4% (55/1,247). The survival rates at 1 year and 5 years were 91.8% +/- 0.8% (+/- the standard error of mean) (n = 1,062) and 79.2% +/- 1.4% (n = 281), respectively. Freedom from valve-related complications (linearized rate, 4.9% per patient-year) at 1 year and 5 years was 90.6% +/- 0.8% (+/- the standard error of the mean) (n = 996) and 80.6% +/- 1.4% (n = 243), respectively. Linearized rates for various complications were as follows: bleeding events, 1.73% per patient-year; embolic events, 1.76% per patient-year; operated valvular endocarditis, 0.18% per patient-year; valve thrombosis, 0.10% per patient year; and nonstructural dysfunction, 1.21% per patient-year. Freedom from reoperation at 1 year and 5 years was 98.6% +/- 0.3% (+/- the standard error of the mean) (n = 1,070) and 97.7% +/- 0.5% (n = 285), respectively. CONCLUSIONS Midterm results demonstrate that the CarboMedics prosthetic heart valve exhibits a low incidence of valve-related complications.

Autotransfusion of washed shed mediastinal fluid decreases the requirement for autologous blood transfusion following cardiac surgery: a prospective randomized trial

OBJECTIVES The National Blood Service issues 2.2 million units of blood per year, 10% of these (220000) are utilized in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We test the efficacy of autotransfusion following surgery in a prospective randomized trial. METHODS One hundred and twelve patients undergoing CABG, valve or CABG + valve procedures were randomized into two groups. Group A received washed postoperative drainage fluid and group C were controls. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a PCV < 30. There was no significant difference in preoperative and operative variables between the groups. RESULTS Twenty-eight patients in group A and 46 in group C required homologous transfusion (P = 0.0008). Group A patients required 298+/-49 ml of banked blood per patient, group C 508+/-49 ml (P = 0.003). There was no difference in total blood required (volume autotransfused + volume banked blood transfused) between the groups (group A 404+/-50 ml, group C 508+/-50 ml) or in mean total mediastinal fluid drainage (group A 652+/-51 ml, group C 686+/-50ml). The mean Hb concentration was significantly higher in group A on day 1 (11.2 g/dl+/-51 vs. 10.6 g/dl+/-13 (P = 0.002)). No morbidity was associated with autotransfusion. CONCLUSION Autotransfusion can decrease the amount of homologous blood transfused following cardiac surgery. This represents a benefit to the patient and a decrease in cost to the health service.

Autotransfusion decreases blood usage following cardiac surgery — a prospective randomized trial

INTRODUCTION 10% of blood issued by the National Blood Service (220,000) is utilised in cardiac procedures. Transfusion reactions, infection risk and cost should stimulate us to decrease this transfusion rate. We tested the efficacy of autotransfusion of washed postoperative mediastinal fluid in a prospective randomized trial. PATIENTS AND METHODS 166 patients undergoing coronary artery bypass grafting (CABG), valve or CABG + valve procedures were randomized into three groups. The indication for transfusion was a postoperative haemoglobin (Hb) < 10 g/l or a packed cell volume (PCV) < 30. When applicable, group A patients received washed post-operative drainage fluid. Group B all received blood processed from the cardiopulmonary bypass (CPB) circuit following separation from CPB and if appropriate washed post-operative drainage fluid. Group C were controls. Groups were compared using analysis of variance. RESULTS There was no significant difference in age, sex, type of operation, CPB time and preoperative Hb and PCV between the groups. Blood requirements were as shown. [table - see text] Twelve patients in group A and 10 in group B did not require a homologous transfusion following processing of the mediastinal drainage fluid. CONCLUSION Autotransfusion of washed postoperative mediastinal fluid can decrease the amount of homologous blood transfused following cardiac surgery. There was no demonstrable benefit in processing blood from the CPB circuit as well as mediastinal drainage fluid.

Effects of angiotensin converting enzyme inhibition on systemic vascular resistance and vasoconstrictor requirements during hypothermic cardiopulmonary bypass

OBJECTIVE We proposed that angiotensin converting enzyme (ACE) inhibitor therapy would alter systemic vascular resistance (SVR) during rewarming and increase the requirement for vasoactive drugs in the immediate post-bypass period. METHODS Sixty-five sequential adult patients undergoing cardiac surgical procedures requiring hypothermic (28 degrees C) cardiopulmonary bypass (CPB) were recruited. Sixty-two fitted the inclusion criteria of which 21 were receiving ACE inhibitors prior to surgery. SVR was calculated at 1 min intervals during the rewarming phase of hypothermic CPB. The use of vasoactive drugs during and immediately after termination of CPB was recorded. The doctor administering these drugs was unaware of the nature of the study. RESULTS Mean SVR in the ACE group was 978 dyne/s per cm5 and in the control group was 1194 dyne/s per cm5 (P = 0.006). Mean arterial pressure was 48.8 mmHg in the ACE group and 56.3 mmHg in the control group (P = 0.004). There was a significant difference in vasoactive drug requirements between the groups (P < 0.01). There was no statistically significant difference in age, weight, body mass index, body surface area, theatre temperature, core temperature at which rewarming started, rate and time of rewarming, haematocrit on bypass or preoperative left ventricular function. CONCLUSION Preoperative ACE inhibitor therapy decreases SVR during the rewarming phase of CPB and increases post-bypass vasoactive drug requirements.

A comparison of transthoracic impedance using standard defibrillation paddles and self-adhesive defibrillation pads

The success of defibrillation is related to transmyocardial current. This current is inversely proportional to transthoracic impedance (TTI). A similar TTI between different pads and paddles is important to deliver a consistent therapeutic dose to all subjects. Failure to do so may result in either insufficient or excessive transmyocardial current leading to a risk of failed defibrillation or tissue damage respectively. Several different types of defibrillation paddles and self-adhesive defibrillation pads are currently available for clinical use but the TTI achieved with each type has not been established. We measured TTI using two types of commonly used paddles and self-adhesive pads to establish whether any significant differences exist between the products. TTI in 40 adult males was measured using defibrillation paddles and self-adhesive defibrillation pads placed in the antero-apical position. Measurements were made using a 30 kHz low amplitude AC current and taken at end-expiration. Mean TTI (omega)+/-S.D. was 68.2+/-16.1 (Hewlett Packard paddles; A), 62.8+/-13.2 (Hewlett Packard pads; B), 64.6+/-14.3 (PhysioControl paddles; C) and 95.6+/-22.3 (PhysioControl pads; D). Significant differences existed between all groups (P < 0.05) except between B and C. Differences in TTI between A, B and C were small and probably of no clinical significance. TTI in group D is significantly larger. Although transmyocardial current is related to TTI, the relationship is complex and differences in TTI alone cannot predict the outcome from defibrillation.

Replacement of the proximal aorta and aortic valve using a composite bileaflet prosthesis and gelatin-impregnated polyester graft (Carbo-Seal): Early results in 143 patients ☆ ☆☆

OBJECTIVE We report the combined early results from two centers in the United Kingdom using a composite conduit consisting of a bileaflet mechanical valve incorporated into a gelatin-impregnated, ultra-low porosity, woven polyester graft (Carbo-Seal; Sulzer Carbomedics, Inc, Austin, Tex). METHODS Between August 1992 and March 1997, 143 patients underwent aortic root replacement with the Carbo-Seal composite prosthesis. The indication for surgery was acute type A dissection in 31 (22%), chronic type A dissection in 9 (6%), ascending aortic aneurysm without dissection in 100 (70%), and false aneurysm of the ascending aorta in 3 (2%). Twenty-seven patients (19%) had undergone previous sternotomy, and 40 (28%) were seen as emergencies. Concomitant procedures were performed in 38 (27%), including 18 aortic arch or hemiarch replacements. Total follow-up is 270 patient-years. Follow-up is 100% complete. RESULTS The early (30-day) mortality was 7% (10 patients). Permanent neurologic events occurred in 2%. At a mean follow-up of 23 months, 94% of survivors were in New York Heart Association functional class I. Freedom from reoperation was 97.2% +/- 1.6% (1 standard error [1 SE]) at 12 months and 95.7% +/- 2.2% at 48 months. Including early mortality, survival was 90.1% +/- 2.6% at 12 months and 83.1% +/- 3. 5% at 48 months. CONCLUSIONS Aortic root replacement with use of the Carbo-Seal prosthesis can be undertaken with a relatively low early mortality and morbidity. A low reoperation rate and high intermediate-term survival can be expected, but continued follow-up is needed to determine the long-term efficacy of this prosthesis.