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Biomedical subjects

D D Muehrcke

Publications and source records attributed to D D Muehrcke.

At least 19 recordsLinked to original sources
PubMed1997

Oral disease burden in patients undergoing prosthetic heart valve implantation.

BACKGROUND: Valvular heart disease predisposing to endocarditis and requiring prosthetic valve implantation is common among the elderly. Spontaneous bacteremias associated with acute or chronic oral/odontogenic infections may represent a far greater cumulative risk for the development of endocarditis than do occasional health care procedures administered in a professional setting. METHODS: To determine the oral disease burden in patients undergoing mechanical or bioprosthetic heart valve implantation, we performed a comprehensive clinical and radiographic regional examination on 156 consecutive patients, with emphasis on identifying acute and chronic oral/odontogenic infections and conditions. RESULTS: The mean number of remaining teeth in the cohort was 19.32; of these, 1.07 were carious, involving a mean number of 2.51 tooth surfaces. In addition, 15.38% of the patients had evidence of acute or chronic periapical abscesses, and 43.6% of the patients had moderate to advanced periodontitis. CONCLUSIONS: In view of the substantial morbidity and mortality associated with prosthetic valve endocarditis and based upon the high incidence of dental disease identified in patients undergoing valvular operations, routine preoperative dental assessment should be deemed a "medical necessity" by third-party payors. Appropriate therapeutic intervention should be initiated whenever possible before valve implantation.

Adult↗
PubMed1997

Is there an advantage to repairing infected mitral valves?

BACKGROUND: The therapy for native mitral valve endocarditis is in evolution. Antibiotics have significantly improved survival rates, but patients with complications of endocarditis may require surgical treatment. METHODS: Between January 1985 and December 1995, 146 patients underwent surgical therapy (repair or replacement) for native mitral valve endocarditis. All patients had documented bacterial endocarditis. Univariate and multivariate analyses were performed to determine predictors of hospital death, long-term event-free survival, and probability of repair. Patients were evaluated in three groups: all patients, patients with acute endocarditis, and patients with chronic endocarditis. RESULTS: There were ten hospital deaths (6.8%). Patients undergoing repair had a lower hospital mortality rate (p = 0.008) then those having replacement. Event-free survival was improved after mitral valve repair in the overall group (p = 0.02) and in the group with healed (chronic) endocarditis (p = 0.05). Although the acute endocarditis group demonstrated an improved event-free survival rate after mitral valve repair versus replacement (74% versus 20% at 6 years), this did not reach statistical significance. CONCLUSIONS: We conclude that mitral valve repair is preferable to mitral valve replacement when possible, in patients with complications of endocarditis, as repair results in a lower hospital mortality and an improved long-term survival.

Adolescent↗
PubMed1997

Reoperation for failure of mitral valve repair.

BACKGROUND AND OBJECTIVE: Mitral valve repair is the procedure of choice to correct mitral regurgitation of all types. Up to 10% of patients who undergo mitral valvuloplasty require late reoperation for recurrent mitral valve dysfunction. To determine the causes of failed mitral valve repair, we examined the surgical pathology of patients who underwent reoperation for failed mitral valve repair. PATIENTS AND RESULTS: From 1986 to 1994, 81 patients had 86 reoperations for recurrent mitral regurgitation after mitral valve repair. Mean age was 59.2 +/- 1.4 years; 55 were men. Primary valve disease was degenerative in 48 patients (59%), rheumatic in 16 (20%), ischemic in 13 (16%), endocarditic in 3 (4%), and congenital in 1 (1%). Mean time interval between initial mitral valve repair and reoperation was 15.6 +/- 2.5 months. Causes of repair failure were procedure-related (50 cases, 58%), valve-related (33 cases, 38%), or unknown (3 cases, 3%). Procedure-related valve failure was caused by suture dehiscence (21 cases), rupture of previously shortened chordae (19 cases), or incomplete initial correction (10 cases). Valve-related repair failure was caused by progressive primary valve disease (27 cases), endocarditis (5 cases), or extensive leaflet retraction (1 case). Repair failure was procedure-related in 70% of patients with degenerative valvular disease versus only 13% of patients with rheumatic valvular disease (p = 0.0001). At reoperation, mitral valve replacement was performed in 64 patients (79%) and repeat mitral valve repair in 17 (21%). CONCLUSION: We conclude that (1) most mitral valve repair failures are procedure-related in degenerative disease and valve-related in rheumatic disease; (2) rupture of previously shortened chordae is a common cause of late failure in patients with degenerative mitral valve disease; and (3) repeat mitral valve repair results in successful treatment for a minority of patients.

Adolescent↗
PubMed1996

Extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock.

BACKGROUND: Extracorporeal membrane oxygenation circuits have recently been introduced for extracorporeal life support (ECLS) in adult patients in cardiogenic shock and have been shown to provide excellent oxygenation and hemodynamic support. Heparin coating of the extracorporeal circuit provides a more biocompatible surface, which has been shown to minimize early surface-induced complement activation and platelet dysfunction and hence may improve patient survival. This report reviews our experience with extracorporeal membrane oxygenation to treat postcardiotomy cardiogenic shock using minimal to no systemic heparinization in 23 patients. METHODS: During the 22-month period September 1992 through July 1994, 23 patients in cardiogenic shock were placed on venoarterial ECLS using a heparin-bonded circuit. These patients' charts were retrospectively reviewed. A logistic regression analysis of the variables collected was performed to identify clear-cut predictors of ability to be weaned from ECLS. RESULTS: Average patient age was 47.3 +/- 16.4 years (range, 5 to 72 years). There were 17 male patients. Average time on ECLS was 58.4 +/- 35.1 hours (range, 0.5 to 144 hours). Statistical analysis revealed that patients unable to be weaned from ECLS were more likely to have a critically dilated left ventricle on echocardiography and were female. Ten patients (43.5%) died while on ECLS. Four patients were transferred to an implantable left ventricular assist device, and 3 underwent successful transplantation. The 9 other patients were successfully weaned from ECLS, and 4 were discharged home from the hospital. Overall, 7 patients (30.4%) who were placed on ECLS were successfully discharged home. CONCLUSIONS: Extracorporeal life support using an extracorporeal membrane oxygenation system provides excellent cardiac support with similar hospital survival rates as centrifugal mechanical support. Extracorporeal life support has complications unique to itself, but with time, these are likely to be overcome. Women and patients with persistent left ventricular dilatation are less likely to be weaned.

Acute Kidney Injury↗
PubMed1996

Biocompatibility of heparin-coated extracorporeal bypass circuits: a randomized, masked clinical trial.

Cardiopulmonary bypass circuits cause morbidity during cardiac operations. Plasma proteins and cellular components are stimulated by contact with the cardiopulmonary bypass circuit and can cause bleeding and postperfusion syndrome. This is especially true in patients undergoing reoperative cardiac procedures, which carries a higher risk of postoperative bleeding and prolonged ventilation compared with primary cardiac surgical procedures. Recently, cardiopulmonary bypass circuit surfaces have been coated with antithrombotic agents to improve their biocompatibility. This study evaluated the effect of a heparin-coated cardiopulmonary bypass system (Duraflo II, Baxter Bentley Healthcare Systems, Irvine, Calif.) on thrombin formation, platelet stimulation, and leukocyte activation in patients undergoing reoperative coronary artery bypass grafting or valve operation. Fifty patients were selected and randomly assigned to a standard noncoated control system (n = 26) or the Duraflo heparin-coated system (n = 24). Similar heparin doses were used in both groups (3 mg/kg). The heparin-coated group used a completely heparin-coated bypass circuit including the cardiotomy reservoir; arterial filters were heparin-coated in both groups. Samples were obtained before cardiopulmonary bypass, 30 minutes into cardiopulmonary bypass, 5 minutes after crossclamp removal, and 5 minutes after protamine administration. Thrombin formation (thrombin-antithrombin III by enzyme-linked immunosorbent assays) and platelet activation (beta-thromboglobulin by enzyme-linked immunosorbent assays; P-selectin expression by flow cytometry) were assayed. Leukocyte activation was determined by quantitative and qualitative analysis of arterial filters by scanning electron microscopy in six patients from each group. In both circuits, thrombin values increased markedly 30 minutes into cardiopulmonary bypass compared with baseline values (p < 0.001) (heparin-coated, 7 +/- 5 to 96 +/- 115 ng/ml; noncoated, 10 +/- 9 to 115 +/- 125 ng/ml). Platelet activation as measured by beta-thromboglobulin (heparin-coated, 104 +/- 100 to 284 +/- 166 IU/ml; noncoated, 81 +/- 74 to 288 +/- 277 IU/ml) and P-selectin expression (heparin-coated, 1.5% +/- 1.5% to 6.4% +/- 6.1%; noncoated, 1.4% +/- 1.1% to 6.2% +/- 4.3%) also significantly increased 30 minutes into cardiopulmonary bypass compared with baseline values (p < 0.001). Platelet activation and thrombin generation did not differ between the two circuits at any time. Granulocyte activation and platelet deposition did not differ between the two circuits when arterial filters were evaluated. Both groups had similar heparin and protamine administration, blood transfusions, postoperative alveolar-arterial oxygen gradient, time to extubation, length of intensive care unit stay, and overall morbidity and mortality. Clinical outcome and blood loss did not differ between the groups. We conclude that heparin-coated cardiopulmonary bypass circuits did not improve biochemical or clinical markers of biocompatibility in a reoperative patient population.

Anticoagulants↗
PubMed1995

Reconstructive airway operation after irradiation.

After a patient died of anastomotic necrosis following a tracheal resection for the management of recurrent thyroid cancer invading the trachea, which had been treated 6 years previously by thyroid lobectomy and 4,800 cGy of radiation to control known residual disease, we explored methods to promote the healing of tissues damaged by irradiation. Between 1979 and 1992, 22 patients underwent major airway resection and reconstruction after receiving large doses of radiation. The average dose was 4,979 +/- 1,113 cGy (range, 3,150 to 6,840 cGy); the number of fractions, 20 to 38; and the average dose per fraction, 180 cGy (range, 150 to 200 cGy). The interval between irradiation and surgical treatment was 42 +/- 105 months (range, 1 to 480 months). Seven cervical, eight midtracheal, and five carinal resections were performed, as well as two mainstem sleeve resections. Omentum was used to protect the anastomosis in 15 patients (68%), a pericardial fat pad was used in 2, and pleura was used in 2. In 3 patients, sternohyoid muscle was placed between the anastomosis and a major vascular structure, but without a tissue wrap. Two patients (9.0%) died postoperatively. Anastomotic dehiscence was the cause of death in a patient treated for lymphoma, and adult respiratory distress syndrome was the cause in the other patient; this patient had undergone carinal pneumonectomy. Complications developed in 8 patients (36%). Two cervical dehiscences were treated by T-tube placement, 2 patients suffered wound infection, and 1 patient each suffered a myocardial infarction, dysphagia, hemoptysis, and bronchitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Surgical and long-term antifungal therapy for fungal prosthetic valve endocarditis.

BACKGROUND: Fungal prosthetic valve endocarditis is an uncommon but serious disease. We have developed a strategy of treatment that includes perioperative amphotericin B, radical debridement of infected tissue, reconstruction using biologic tissue when possible, and prolonged oral suppressive antifungal therapy. METHODS: We retrospectively reviewed the charts of 12 patients reoperated on for fungal prosthetic valve endocarditis involving the aortic valve (10 patients: six porcine valves, two mechanical valves, two homografts) and the mitral valve (2 patients, both porcine valves). Prosthetic valve endocarditis developed in 7 within 12 months after the first valve procedure. The organisms included Candida species (9 patients), Scopulariopsis brevicaulis (1), Saccharomyces cervisiae (1), and histoplasmosis (1). RESULTS: At operation, all patients had prosthetic vegetations, 8 had abscesses, and 4 had sinus tracts. Seven received aortic homografts, 4 received porcine valves (two mitral), and 1 received a mechanical prosthesis. Two patients died in the hospital after prolonged illnesses (83% hospital survival). Four patients had recurrence an average of 25 months later and 3 underwent further surgical intervention. One patient had recurrence and died 17 months postoperatively. One other late death occurred 96 months after operation, and there was no evidence of recurrence. Eight patients (67%) are alive and well 51.5 +/- 61.0 months (range, 1 to 189 months) after the first redo procedure for fungal prosthetic valve endocarditis. CONCLUSIONS: We conclude that preoperative treatment with amphotericin B, radical resection of all infected tissue, cardiac reconstruction using biologic tissue when possible, and life-long oral antifungal therapy is effective for fungal prosthetic valve endocarditis.

Abscess↗
PubMed1995

Complications of extracorporeal life support systems using heparin-bound surfaces. The risk of intracardiac clot formation.

Extracorporeal life support with heparin-coated extracorporeal membrane oxygenation circuits are being used with increased frequency in patients who have cardiogenic shock. We report our experience in 30 patients with cardiogenic shock, looking specifically at the complications associated with this form of life support. Thirty patients with a mean age of 46.5 +/- 16.6 years received extracorporeal life support for a mean of 62.8 +/- 41.1 hours (range 0.5 to 159 hours). Twenty-three patients had postcardiotomy cardiogenic shock, five had acute myocardial infarction, and one each had acute cardiac deterioration after a balloon coronary angioplasty and another after pulmonary artery balloon angioplasty. Peripheral (femoral vein to femoral artery) cannulation was used in 24 patients. Limb ischemia developed in 21 patients (70%), renal failure in 17 patients (57%), oxygenator failure requiring change in 13 patients (43%), bleeding requiring reexploration in 12 (40%), and infection in 9 patients (30%). Transesophageal echocardiography revealed intracardiac thrombus formation in 6 patients (20%) and clot was visualized grossly in the pump head in 2 patients (6%) necessitating pump-head change. Nine patients (30%) were discharged home. We conclude that the use of heparin-coated extracorporeal life support without systemic heparinization, especially after protamine has been used to reverse systemic heparinization in patients having postcardiotomy cardiogenic shock, may be dangerous. Extracorporeal life support has introduced new complications unique to itself specifically limb ischemia, oxygenator failure, and pump-head thrombus.

Adolescent↗
PubMed1995

Flow characteristics of aortic cannulae.

Atheroembolism from the ascending aorta is an emerging cause of noncardiac complications after open heart surgery. We designed a new arterial cannula specifically to reduce the exit force and velocity of blood flow, thereby reducing the "sandblasting" effect of the exiting blood jet. The cannula has a closed tip and an internal cone that diffuses blood flow such that it enters the aorta via multiple side holes. Fluid dynamics of the cannula were tested against five frequently used cannulae: Sarns High-Flow (3M Sarns High-Flow, Ann Arbor, MI, USA), DLP 83024 (DLP Inc., Grand Rapids, MI, USA), RMI ARS 024C (Research Medical Inc. of Research Industries Corp., Midvale, UT, USA), Bard 1966 (C.R. Bard Inc., Haverhill, MA, USA), and Argyle THI (Sherwood Medical Co. Sub American Home Products Corp., St. Louis, MO, USA). All cannulae had an 8.0-mm external diameter. The new cannula demonstrated a similar pressure drop and internal tip diameter as the others. The exit force (newtons) of the Soft Flow cannula was significantly less than the Sarns High-Flow (p < 0.05), DLP (p < 0.001), RMI (p < 0.01), Bard (p < 0.001), and the Argyle (p < 0.001) cannulae. Peak velocity (cm/s) of the Soft Flow cannula was significantly less than the DLP (p < 0.01), RMI (p < 0.01), Bard (p < 0.01), and Argyle (p < 0.001). The cannulae all had similar hemolysis rates. The new arterial cannula produced the lowest exit force and flow velocity with no increase in hemolysis and may help to decrease the incidence of atheroemboli and its sequelae.

Cardiac Surgical Procedures↗
PubMed1995

Fungal prosthetic valve endocarditis.

Fungal prosthetic valve endocarditis is an unusual cause of endocarditis, yet very important because of its historical poor prognosis. This article will review the incidence, presentation, diagnosis, and treatment results of fungal prosthetic valve endocarditis. In addition, 11 patients at The Cleveland Clinic over the last 16 years were treated with a strategy consisting of aggressive perioperative amphotericin B therapy, radical surgical debridement of all infected tissue and prosthetic valve replacement with biological tissue when possible, as well as the chronic use of oral azole antifungal agents for suppression. This combined approach has resulted in 82% of patients being discharged and a 55% 5-year survival rate. Unfortunately, 36% of patients developed recurrent fungal prosthetic valve endocarditis, at an average of 25.8 months after their first operation for fungal prosthetic valve endocarditis. The use of oral antiazole antifungal agents for suppression may prevent the high incidence of recurrent endocarditis in this patient population.

Amphotericin B↗
PubMed1995

Current surgical approach to acute ventricular septal rupture.

The recent advances in the management of postinfarct ventricular septal rupture have helped to decrease the operative mortality rate to 10% in one series. The addition of coronary artery bypass grafting seems to improve long-term survival despite having little effect on hospital mortality. Recent technical improvements have helped to decrease postoperative bleeding and may preserve ventricular function. Patients undergoing shunt repair today tend to be older and more likely to have received thrombolytic agents, which may complicate the repair. Survival and quality of life are excellent even in patients older than 70 years after successful repair.

Acute Disease↗
PubMed1993

Warm heart surgery in patients with cold autoimmune disorders.

Continuous warm antegrade delivery of cardioplegia while maintaining systemic normothermia is a new method of performing coronary artery bypass grafting. It can be used to avoid the detrimental effects of hypothermia in patients with cold autoimmune disease.

Aged↗
PubMed1992

Postinfarct ventricular septal defect repair: effect of coronary artery bypass grafting.

Between June 1968 and April 1991, 75 patients who had undergone coronary angiography underwent repair of a postinfarction ventricular septal defect. Group 1 (n = 33) includes patients who had two- or three-vessel serious (> 75% narrowing) proximal coronary artery disease and underwent complete revascularization in addition to repair of the ventricular septal defect. Group 2 (n = 19) patients also had two- or three-vessel coronary artery disease but bypass grafting was not performed; only the ventricular defect was repaired. Group 3 (n = 23) patients had only single-vessel coronary artery disease that corresponded to the region of the infarct; they underwent ventricular septal defect repair only. Follow-up of hospital survivors was 96% complete at a mean of 86.2 months (range, 1 to 288 months). Hospital mortality after ventricular septal defect repair was 21.2% in the cohort with bypassed coronary artery disease (group 1), 26.3% in those with unbypassed disease (group 2), and 26.1% in those with only single-vessel coronary artery disease (group 3) (p = 0.88). With follow-up after 5 and 10 years, the actuarial survival was 72.2% +/- 8% and 47.8% +/- 10%, respectively, in the bypassed group, 29.2% +/- 11% and 0%, respectively, in the unbypassed group, and 52.2% +/- 10% and 36.5% +/- 11%, respectively, in the cohort with single-vessel disease. Bypassing associated coronary artery disease significantly increased long-term survival when compared with patients with unbypassed coronary artery disease (p = 0.0015).

Aged↗
PubMed1992

Survival after repair of postinfarction ventricular septal defects in patients over the age of 70.

Ventricular septal defect (VSD) is an infrequent but extremely serious complication of myocardial infarction. Operative mortality rates tend to be higher in the elderly population; however, long-term follow-up has not been specifically studied. It is, therefore, important to assess not only the early but also the long-term results of VSD repair in patients over 70 years of age to determine its value for the elderly patient. Between June 1968 and May 1991, 86 patients who experienced a myocardial infarction underwent surgical repair of an infarct related VSD at the Massachusetts General Hospital (MGH). Group I (n = 57) includes those patients younger than 70 years, and group II (n = 29) represents those patients age 70 years and older. Follow-up of hospital survivors ranged from 1 month to 24 years and was compiled in April and May, 1991. Three patients were lost to follow-up (4%), and these were younger than 70 years of age. There were no differences in the values of the preoperative variables for the younger and older groups with respect to sex, concomitant procedures performed (bypass vs no bypass), use of an intra-aortic balloon pump (IABP), location of VSD, presence of shock, total hospital days, or days between infarction and operation. There was, however, a difference between the two groups relative to the era when surgery was performed. More patients over the age of 70 underwent surgery after 1978 than before 1978 (p = 0.0012). The majority of survivors are in New York Heart Association (NYHA) Class I or II, and there was no difference between the younger and older groups in functional class at the time of follow-up (83.3% vs 91.7% of survivors in Class I or II, respectively). Using the generalized Wilcoxon test to analyze these survival data, there was no apparent difference in long-term survival (p = 0.97) when comparing the two age groups. The mean follow-up period was 77.02 months for the younger group and 80.52 months for the older group. The fact that more older patients were repaired after we had significant experience in the surgical management of patients with VSDs probably accounted for our excellent results in the older age group. Our data reveal that patients over the age of 70 can expect excellent long-term survival, with over 90% of these survivors remaining in NYHA Functional Class I or II.

Adult↗
PubMed1991

Laryngotracheoesophageal cleft (type IV): management and repair of lesions beyond the carina.

Since the first successful repair of a complete laryngotracheoesophageal cleft (LTEC) to the carina in 1982, three newborn infants were observed with a particularly difficult variant in which the cleft extends beyond the carina into the mainstem bronchi. This type IV LTEC creates a long common tracheoesophagus, whose successful separation requires meticulous preoperative, operative, and postsurgical care. Three infants had complete surgical repair at our institution at 29, 49, and 225 days old and survived a minimum of 8 months. Recurrent tracheoesophageal fistulae at the thoracic inlet occurred in two infants, but was not observed in one patient when sternocleidomastoid muscle was interposed between the trachea and esophagus in the neck. Microgastria is an associated finding in each infant with the tracheoesophageal cleft extending beyond the carina. The small stomach is problematic as it is anatomically inadequate for any antireflux procedure and has not grown well, even with prolonged feeding. Early cleft repair is essential to prevent the development of chronic lung disease secondary to recurrent aspiration. The techniques to make the diagnosis, the preferred treatment to initially protect the airway, a single-stage operation performed simultaneously through the chest and neck to definitively repair the cleft, and finally the intraoperative and postoperative management critical for an optimal outcome are described.

Abnormalities, Multiple↗