Hemodynamic effect of sustained pulmonary hyperinflation in patients after cardiac surgery: open vs. closed chest.

BACKGROUND: In a previous study, we showed that sustained pulmonary hyperinflation, i.e. a lung recruitment maneuver, after closure of the chest in patients undergoing cardiac surgery had significantly negative effects on the central hemodynamics. As elevated pleural pressure is believed to be a major cause of this cardiovascular impairment, we hypothesized that performing the sustained pulmonary hyperinflation under open chest conditions would affect the circulation less. METHODS: Patients undergoing cardiac by-pass surgery were included and sustained pulmonary hyperinflations (40 cmH(2)O airway pressure for 15 s) were performed immediately before and after closure of the sternum. Pulse contour cardiac output, heart rate, mean arterial pressure and pulse pressure variation were measured before, during and 1 min after the hyperinflations. Left ventricular dimensions were measured using trans-esophageal echocardiography. RESULTS: Cardiac output (CO) and mean arterial blood pressure (MAP) decreased significantly during the sustained pulmonary hyperinflation both with an open and closed chest (in parenthesis): CO by 50 (45)% and MAP by 19 (24)%. The left ventricular end-diastolic area was significantly reduced by 24 (33)%. One minute after the hyperinflation, all measured variables had returned to baseline values. No significant differences in the measured variables were found between the two conditions before, during or 1 min after the hyperinflation. CONCLUSION: Contrary to our hypothesis, sustained pulmonary hyperinflations with the chest open, i.e. before sternal closure, had similar negative effects on central hemodynamics as those performed with the chest closed, i.e. after sternal closure.

Twelve years' clinical experience with the CarboMedics prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: The CarboMedics bileaflet prosthetic heart valve was first implanted as part of a prospective clinical study at the authors' institution in November 1987. The patient cohort included was part of a multicenter trial set up by the manufacturer for an FDA application. The present report details findings over a 12-year period, with a continuous follow up on this patient cohort. METHODS: Between November 1987 and August 1990, 132 patients (68 males, 64 females; median age 56 years; range 12-74 years) received a CarboMedics heart valve prosthesis. All patients were included in the study, whether surgery was elective or emergency, first time or reoperation. There were 69 aortic, 49 mitral and 12 double (aortic + mitral) valve replacements. Two patients had isolated tricuspid valve replacement. Concomitant surgery was performed in 15 patients. Anticoagulation with warfarin was started on postoperative day 1. After discharge, patients were examined regularly as outpatients for up to five years. Subsequent follow up was obtained prospectively by questionnaires to the patients' general practitioner, or by telephone calls. Actuarial estimates of survival and freedom from morbid events were calculated using the Kaplan-Meier method; 95% confidence limits for the distribution function were calculated according to the Greenwood formula. RESULTS: Complete follow up information was available for 94% of the patients; total follow up was 1,014.3 patient-years (pt-yr). Actuarial survival at 12 years was 62 +/- 0.5% overall (61 +/- 6.5% for aortic; 66 +/- 7.5% for mitral; 65 +/- 14.0% for double valve replacements). Actuarial rates of freedom from complications were: valve thrombosis 100%, embolism 92 +/- 2.8%, and anticoagulant-related bleeding 77 +/- 5.6%. The linearized rates per 100 pt-yr were: embolism 0.89 (aortic 0.74, mitral 1.30); anticoagulant-related bleeding 2.56; paravalvular leakage overall 0.20 (aortic 0.37); prosthetic valve endocarditis overall 0.20 (aortic 0.37). There was no hemolysis, prosthetic valve dysfunction or structural deterioration. CONCLUSION: Over a 12-year time frame, the CarboMedics prosthetic heart valve has proven to be a highly reliable device with no structural failures, and a low incidence of valve-related complications.

Recurrent endocarditis in silver-coated heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: In order to prevent prosthetic valve endocarditis (PVE), the implantation of a new silver-coated sewing ring has been introduced to provide peri- and postoperative protection against microbial infection. METHODS: A 56-year-old woman with aortic stenosis had elective replacement with a St. Jude Medical mechanical valve fitted with a silver-coated sewing ring (Silzone). The patient developed early PVE, which necessitated reoperation after one month. Despite a second Silzone prosthesis being implanted, the endocarditis recurred. During a third operation an aortic homograft was implanted, and after six months a fourth operation was performed for a pseudoaneurysm at the base of the homograft, in proximity to the anterior mitral valve leaflet. RESULTS: The diagnosis of PVE was confirmed by the presence of continuous fever, transesophageal echocardiography and growth of penicillin-resistant Staphylococcus epidermidis from the valve prosthesis. CONCLUSION: The implantation of all prosthetic valves is encumbered with a risk of endocarditis. Although silver has bacteriostatic actions, the advantages of silver-coated prostheses in the treatment of this condition have yet to be assessed in clinical trials.

Treatment of aortic valve endocarditis with the Ross operation.

OBJECTIVE: Standard treatment of patients with infective endocarditis is radical debridement and valve replacement, in cases with advanced pathology the treatment is usually root replacement with either a composite graft or a homograft. Enthusiasm for the use of the Ross operation in non-infective aortic valve disease is increasing, but use of the pulmonary autograft in the treatment of aortic valve endocarditis has been limited. The objective of this prospective study is to present the technique and results of our experience with aortic valve endocarditis treated with the Ross operation. MATERIALS AND METHODS: Since 1992 we have treated 35 patients (median age 41 years, range 6-71 years) having aortic valve endocarditis with a Ross operation. Twenty-four patients had advanced disease defined as pathology due to endocarditis extending beyond the valve cusps (13 patients) or prosthetic valve endocarditis (11 patients). Twenty-two patients had active disease at the time of surgery, and 12 had undergone one to four previous heart operations. RESULTS: There were two operative deaths (5.8%), both related to severe disease with very advanced pathology and heart failure. Intraoperative echocardiography demonstrated no or trivial autograft insufficiency in all patients. There have been no late deaths. There has been one (probable) recurrent right-sided endocarditis in a drug addict during a follow-up period of 3-56 months. One patient has been reoperated on for homograft stenosis. CONCLUSIONS: We are enthusiastic about the use of the Ross operation in aortic valve endocarditis and in younger patients with advanced pathology, it is our preferred treatment modality. Following removal of the autograft, unparalleled exposure of the left ventricular outflow tract is obtained. Even in patients with very advanced pathology the left ventricular outflow tract is usually intact, allowing autograft implantation in the standard fashion. For selected patients with simple endocarditis, the Ross operation is an attractive option on its usual merits.

Efficacy and safety of dofetilide, a new class III antiarrhythmic agent, in acute termination of atrial fibrillation or flutter after coronary artery bypass surgery. Dofetilide Post-CABG Study Group.

Ninety-eight patients, who developed atrial fibrillation/flutter after coronary artery bypass grafting within 1-6 days after surgery, were included into a double-blind, placebo-controlled, randomized trial to assess the efficacy and safety of dofetilide. Patients were randomly allocated to dofetilide 4 micrograms/kg i.v. (n = 33), dofetilide 8 micrograms/kg i.v. (n = 32) or placebo (n = 33) given intravenously over 15 min at a constant infusion rate. Responders were defined as patients who converted to sinus rhythm at any time during the initial 3 h after the start of the infusion. The conversion rates were 24% (8/33) on placebo, 36% (12/33) on dofetilide 4 micrograms/kg, and 44% (14/32) on dofetilide 8 micrograms/kg. The P-values (two-tailed) were 0.27 for dofetilide 4 micrograms/kg vs. placebo, 0.11 for dofetilide 8 micrograms/kg vs. placebo, and 0.10 for dose-response relationship. Short episodes of aberrant ventricular conduction and ventricular tachycardia were seen separately in three subjects after dofetilide 8 micrograms/kg. No episodes of torsades de pointes were noted. No negative inotropic effect was noted. In conclusion, dofetilide was well tolerated, but the effects on atrial fibrillation/flutter did not attain statistical significance, possibly due to the high placebo conversion rate.

Early autograft endocarditis after Ross operation: a case history.

A case of early autograft endocarditis occurring three weeks after a Ross operation is described. The origin of the infection appeared to be the proximal suture line of the autograft and the pathology included subvalvular destruction of the autograft, a pseudoaneurysm between the autograft and the left atrium, and a fistula to and a vegetation in the roof of the left atrium. The valve cusps were unaffected and there was only slight autograft insufficiency (grade I-II). The autograft was removed and successfully replaced with a homograft.

Changing indications for the Ross operation.

The first Ross operation in Copenhagen was performed in 1992, and from the beginning of the series, which now numbers 80 patients, the underlying philosophy has been based on our belief that the autograft/Ross operation possesses a number of important and unique advantages compared with other alternatives, particularly for patients with complicated aortic valve disease in which alternative treatments are not satisfactory. The series includes patients of 6 weeks to 71 years of age, many with complicating conditions (endocarditis, 24 patients [native valve, 15; prosthetic valve, 9; advanced 17; active, 15; healed, 9], prosthetic valve dysfunction, 4; small aortic root, 2; ascending aortic aneurysm, 5; ventricular septum defect, 2; mitral valve disease, 7; tricuspid valve disease, 2; rheumatic heart disease, 7; aortic annular dilatation, 2; coronary artery disease, 4; extreme obesity, 1; severely reduced left ventricular function, 7; and previous heart surgery, 28). Mortality is low: hospital mortality, 3 patients (3.75%); late mortality, 1 patient (1.25%). Three patients have required reoperation, however; 1 because of autograft insufficiency and 2 because of pulmonary homograft stenosis, but autograft function is good in 73 (< or = 1+) and acceptable (< or = 2+) in 3 patients, and seems to be stable at follow-up. All in all, the early results are encouraging. We are particularly enthusiastic about the Ross operation for patients with complicated aortic valve pathology such as endocarditis, the small aortic root, combined valvular and subvalvular stenosis, and we believe that the Ross operation may be the best operation for these patients.

Prevalence of left ventricular hypertrophy in a hypertensive population.

AIMS: This investigation was set up to study the prevalence of left ventricular hypertrophy in a hypertensive population with reference to a normotensive control group. From the general population 3498 men and women aged 35, 45, 55 and 65 years old were invited to a health examination. Participants with blood pressure above 160 mmHg systolic or 95 mmHg diastolic or those taking antihypertensive medication or having done so during the previous 6 months were asked to undergo an echocardiographic examination. Normotensive controls were randomly selected from the same population. Of 552 participants in the final study population, 194 were normotensive controls and 358 were in the hypertensive group. Echocardiographic measurements were made according to the Penn conventions and indexed for body surface. Cut-off values for left ventricular hypertrophy were 134 g.m-2 for males and 102 g.m-2 for women. RESULTS: Overall, the prevalence of left ventricular hypertrophy was 14%/20% (men/women) in normotensives and 25%/26% in hypertensives (P < 0.01). After subdivision by age and sex, there was a significant difference in the prevalence of left ventricular hypertrophy between normotensives and hypertensives only in the 65-year-old group (P < 0.02 for males and P < 0.05 for females). CONCLUSIONS: The association between blood pressure and left ventricular hypertrophy in the general population is weak. Left ventricular hypertrophy is only significantly more frequent among hypertensives as compared to normotensives in older people.

Intraoperative echocardiographic study of air embolism during cardiac operations.

BACKGROUND: Central nervous system damage remains a feared complication after heart operations. Air embolism (AE) is one of several possible causes of central nervous system damage. In previous studies, intraoperative transesophageal echocardiography (ITEE) has been used to detect AE, but identification of the periods of risk and the origin of AE is lacking. METHODS: Two groups of patients undergoing elective heart operations were studied with ITEE. Group I consisted of 15 patients undergoing true "open heart" operations, either aortic or mitral valve. Group II consisted of 15 patients undergoing coronary artery bypass grafting. RESULTS: In group I (valve operation), ITEE detected AE in all patients, particularly in the period between the release of the aortic cross-clamp and the termination of cardiopulmonary bypass. Furthermore, 12 of the 15 patients had new episodes of AE up to 28 minutes after termination of cardiopulmonary bypass. In the majority of cases, ITEE clearly demonstrated that the air originated in the lung veins and was not air retained in the heart. In group II (coronary artery bypass grafting) episodes of AE were only seen in the period between cross-clamp removal and the termination of cardiopulmonary bypass, and only in half of the patients. CONCLUSIONS: Careful standard cardiac deairing did not prevent AE caused by the delayed release of air trapped in the lung vessels. Routine use of ITEE is recommended to assess the thoroughness of deairing procedures. This will help eliminate AE or at least lead to an increased awareness of the problem of retained air. Minimizing AE during open heart operations should contribute to a reduction in central nervous system damage and improvement of intellectual function after heart operations.

Perivalvular cavities in endocarditis: abscesses versus pseudoaneurysms? A transesophageal Doppler echocardiographic study in 118 patients with endocarditis.

The appearance of perivalvular cavities (PCs) in patients with infectious endocarditis (IE) was studied by transesophageal echocardiography (TEE) color Doppler examinations to determine whether the color Doppler TEE presentation was in keeping with the current concept of PCs representing abscesses. Two heart centers participated in the study. Videotape recordings of TEE examinations in patients with IE were analyzed retrospectively for 18 months in both centers, and one center included patients prospectively for an additional 18 months. A total of 118 patients with a diagnosis of IE based on TEE and clinical and laboratory findings were seen during the study period. TEE showed PCs in 34 patients. In 3 patients who died, no autopsy was performed; the PCs were proved at autopsy or surgery in the remaining 31 patients, who constituted the study population. All PCs were echo free at TEE. Apart from one technically inadequate examination, all PCs contained color Doppler signals indicating intracavitary blood flow; the PCs communicated through a narrow channel with high-pressure regions (the left ventricle or the ascending aorta). At surgery or autopsy, only 2 of the 31 patients had pus accumulations besides the blood-filled PCs. At TEE the pus accumulations presented as echo-rich, shaggy tissue thickening. It is concluded that well-delineated, echo-free PCs with intracavitary color Doppler signals at TEE appear to be pseudoaneurysms, and therefore the term abscess should not be used in these cases. Although further studies are needed, our findings suggest that PCs more likely occur by infectious tissue weakening and subsequent dissection rather than as a result of primary abscess formation with secondary rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Expanding indications for the Ross operation.

During the past 2.5 years, 50 Ross operations have been performed at Rigshospitalet in Copenhagen in a broad range of patients with aortic valve disease including children and adults from 6 weeks to 71 years of age. Many patients had complicating conditions including endocarditis (n = 13, eight native, five prosthetic valve), prosthetic valve dysfunction (n = 4), subvalvular obstruction (n = 3) treated by septal myectomy (n = 1) or modified Konno operation (n = 2), ascending aortic aneurysm (n = 2), ventricular septum defect (n = 1), mitral valve disease (n = 6), rheumatic heart disease (n = 4), coronary artery disease (n = 1), and extreme obesity (n = 1). All operations were performed as free-standing total aortic root replacements. The results have been encouraging with low mortality (2%) and no major morbidity. One patient has been reoperated because of autograft insufficiency due to left coronary cusp prolapse and two additional patients have grade 2 autograft insufficiency and are being followed closely. Two patients have developed early pulmonary homograft stenosis, which has required pulmonary homograft replacement. Despite these problems, we are enthusiastic about this operation and believe it may emerge as operation of choice for most patients under 60-65 years of age with aortic valve disease and for patients with prosthetic or advanced native aortic valve endocarditis. With increasing frequency, our choice has been to proceed with a Ross operation, and currently, our only absolute contraindication is Marfan's syndrome. Based on reported recurrent disease in patients with rheumatic valve disease, the autograft should be used with caution for this indication.(ABSTRACT TRUNCATED AT 250 WORDS)

The Ross operation: results of early experience including treatment for endocarditis.

The Ross operation has been performed for more than 25 years and its popularity has increased dramatically in recent years. We developed an interest in this procedure through a combination of a basic dissatisfaction with a device that requires life-long anticoagulation and the belief that a vital, autologous tissue valve with normal valve morphology and hemodynamics would prove to be superior to the mechanical valve, and that these advantages would outweigh the potential drawbacks related to the operation's technical difficulty and the risk of autograft or homograft dysfunction. From December 1992 to November 1994 40 Ross operations as total root replacements in a diverse group of patients between 5 and 72 years of age (median 32) were performed at Rigshospitalet. Seventeen (43%) of the patients had undergone at least one previous open heart operation. Eleven patients (28%) required surgery because of ongoing or previous endocarditis, and of these, nine had aortic annular destruction and cavity/pseudoaneurysm formation and five had prosthetic valve endocarditis. Three patients (8%) were operated because of mechanical valve dysfunction. One patient was treated for an ascending aortic aneurysm and aortic insufficiency. The remaining 25 patients were operated because of congenital or acquired aortic insufficiency, stenosis, or both. Ten patients (25%) underwent concomitant procedures. No mortality or serious complications occurred. Morbidity was limited to one case each of total atrioventricular (A-V) block, sternal pseudarthrosis, minor stroke, and deep vein thrombosis. Thirty-five patients had no or trivial, two patients mild, and three patients moderate autograft valve insufficiency during a median follow-up of 8 months (range 0-23 months). Two patients had pulmonary stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

The Ross operation in the treatment of prosthetic aortic valve endocarditis.

Prosthetic aortic valve endocarditis is associated with significant morbidity and mortality despite aggressive medical and surgical treatment. In most cases, surgery is the only curative treatment modality, and these operations can be extremely challenging due to often extensive perivalvular tissue destruction. The currently recommended treatment for these advanced infections is thorough debridement and aortic root replacement with a homograft, although it seems that equally good results can be achieved with composite valved conduits. Enthusiasm for the use of the pulmonary autograft as described by Ross for the treatment of noninfective aortic valve disease is increasing, but use of the pulmonary autograft in the treatment of aortic valve endocarditis is uncommon. We have used the Ross operation as total root replacement with success in 11 patients with native or prosthetic aortic valve endocarditis. This article describes the use of this treatment modality in five of these patients between 10 and 72 years of age with prosthetic aortic valve endocarditis. Follow-up extending to 22 months shows excellent results with no mortality and no reinfection. The pulmonary autograft seems to be technically and uniquely well suited for these cases, and it has growth potential, excellent hemodynamics, and a low risk of reinfection, thrombosis, and embolic complications, without anticoagulation.

Casual blood pressure in a general Danish population. Relation to age, sex, weight, height, diabetes, serum lipids and consumption of coffee, tobacco and alcohol.

A population survey was conducted on 3608 randomly selected Danes aged 30, 40, 50 and 60 years respectively. Of these, 3400 were not in medical treatment for arterial hypertension. The following parameters were investigated: sex, age, serum lipid levels (total cholesterol, HDL cholesterol, triglycerides), presence of diabetes mellitus, height, body mass index (BMI), and average daily consumption of coffee, tobacco and alcohol. Analysis with multiple linear regression showed that all variables with the exception of triglycerides, HDL cholesterol and height were significantly associated with systolic blood pressure. Likewise all factors except diabetes, triglycerides and height were significantly associated with diastolic blood pressure. Further analysis in which the effect of each parameter was corrected for by the effects of the remaining variables, demonstrated that apart from age and sex only BMI and high alcohol consumption were positively associated with differences in blood pressure greater than a few mmHg. However, the variation in both systolic and diastolic blood pressures was only partly accounted for by the parameters studied--in the covariates analysis R2 for systolic blood pressure was 0.28 and R2 for diastolic blood pressure was 0.30. In conclusion, this investigation demonstrated that blood pressure is relatively independent of other factors important in the development of cardiovascular disease. Of the above-mentioned factors with some influence on blood pressure only age, BMI and high alcohol consumption have potential clinical importance.

[Switching of the great vessels (arterial switch surgery) in transpositio vasorum]. / Omskifning af de store kar (arteriel switch operation) ved transpositio vasorum.

Since April 1992 the arterial switch operation (ASO) has been the treatment of neonates with transposition of the great arteries (TGA) at Rigshospitalet, Copenhagen. Thirteen mature neonates with TGA underwent ASO. Ten patients had simple TGA, two had TGA associated with a ventricular septal defect (VSD), and one had TGA with VSD and in addition moderate right ventricular hypoplasia. All patients survived the operation and are still alive. Perioperative bleeding was a problem in three cases. Eleven patients had an uncomplicated postoperative course. One patient had peri- and postoperative left ventricular failure and was reoperated after three months for a residual VSD. One child developed renal failure and needed peritoneal dialysis. The patients have been followed for 5.5 (range 0-12) months, they are all in good condition and thriving well. The presented early results after ASO justify continued recommendation of ASO as the operation of choice for TGA in neonates at Rigshospitalet.

Surgical repair of a postendocarditis abscess cavity in the heart guided by intraoperative transoesophageal echocardiography.

A case of aortic prosthetic endocarditis is presented that was complicated by the formation of a cavity in the spatium between the aorta and the roof of the left atrium. At the primary operation this cavity had not been detected. During reoperation the surgeon localized the cavity in the cardioplegic heart, guided by transoesophageal echocardiography.