Diagnosis and management of complications of prosthetic heart valves

Percutaneous Closure of Mitral Paravalvular Leak: Long-Term Results in a Single-Center Experience

Background: Paravalvular leak occurs in 5–17% of patients following surgical valve replacement, more often in mitral position. The prognosis without treatment is poor. Percutaneous device closure represents an alternative to repeat surgery. The objective of this work is to evaluate the medium and long-term results in the percutaneous closure of PVL in mitral prosthesis. Methods: This observational study is based on a retrospective registry including consecutive mitral PVL cases undergoing percutaneous closure at a single tertiary-care center from April 2010 to December 2020. The safety and efficacy results of the procedure, at 90 days and in the long term, were analyzed. Also, predictors of procedure failure and long-term events were identified. Results: A total of 128 consecutive mitral paravalvular leak closure procedures were included. Technical success was achieved in 115 (89.8%) procedures. The presence of multiple PVLs was the sole factor that independently predicted procedural failure. Median follow-up of our sample was 41.8 months (mean 47.7 ± 35.7 months). Underlying hemolytic anemia as the indication for PVL closure, a recent admission for decompensated HF, and lack of improvement in functional class emerged as consistent predictors of MACE and death during long-term follow-up, while lack of procedural success during the first PVL procedure and chronic kidney disease were also associated with MACE during follow-up. Conclusions: Percutaneous mitral PVL closure displayed high technical and procedural success rates, with an acceptable safety profile, in a high-risk population. Percutaneous mitral PVL closure achieved an improvement in short- and long-term functional class and a reduction of hemolysis in the vast majority of patients. In addition, long-term survival in our study was good, in particular for patients undergoing successful PVL closure procedures.

Use of Computational Fluid Dynamics to Analyze Blood Flow, Hemolysis and Sublethal Damage to Red Blood Cells in a Bileaflet Artificial Heart Valve

Artificial heart valves may expose blood to flow conditions that lead to unnaturally high stress and damage to blood cells as well as issues with thrombosis. The purpose of this research was to predict the trauma caused to red blood cells (RBCs), including hemolysis, from the stresses applied to them and their exposure time as determined by analysis of simulation results for blood flow through both a functioning and malfunctioning bileaflet artificial heart valve. The calculations provided the spatial distribution of the Kolmogorov length scales that were used to estimate the spatial and size distributions of the smallest turbulent flow eddies in the flow field. The number and surface area of these eddies in the blood were utilized to predict the amount of hemolysis experienced by RBCs. Results indicated that hemolysis levels are low while suggesting stresses at the leading edge of the leaflet may contribute to subhemolytic damage characterized by shortened circulatory lifetimes and reduced RBC deformability.

Valvular Hemolysis Masquerading as Prosthetic Valve Stenosis

The evaluation of prosthetic valves can provide a unique challenge, and a thoughtful approach is required. High output states like anemia should be kept in the differential when evaluating elevated gradients across prosthetic valves. We present the case of a 69-year-old man with a Starr-Edwards prosthetic aortic valve who presented with symptoms of congestive heart failure and high transvalvular pressure gradients. These symptoms indicate a potential prosthetic valve stenosis. His laboratory evaluation results were consistent with valve-related hemolysis. Resolving his anemia led to a resolution of the symptoms and lowered the pressure gradient on follow-up.

Iatrogenic Cardiovascular Disease Secondary to Diagnostic and Therapeutic Procedures

The number of diagnostic and therapeutic procedures performed in cardiology continues to grow. These pro cedures are generally considered safe or of minimal risk to the patient. However, it is important to remember that significant complications may occur, and in each patient the risk: benefit ratio must be carefully weighed. In this review, the complications documented in the medical literature resulting from the use of cardiologic interventions and procedures are discussed. A thorough knowledge of these complications and their precipitat ing factors can help minimize the risk to the patient.

Device closure of periprosthetic paravalvular regurgitation

Periprosthetic paravalvular regurgitation is an important sequel associated with prosthetic valves whether implanted surgically or via transcatheter approach. They can remain clinically silent or manifest as clinical heart failure, intravascular hemolysis or a combination of both. Periprosthetic defects are becoming increasingly recognized as a source of morbidity and mortality in patients with prosthetic heart valves and in the last few years, the management of this condition has evolved. This review aims to address the current knowledge on the pathophysiology, imaging modalities and management of these defects. It further details the principles, methodology and outcomes of catheter-based device therapy of periprosthetic paravalvular defects.

Effect of valve suture technique on incidence of paraprosthetic regurgitation and 10-year survival

BACKGROUND

The primary objective was to estimate the risk of paraprosthetic regurgitation (PPR) after aortic (AVR) and mitral valve replacement (MVR) using interrupted (IN) or semicontinuous (SC) sutures. The secondary objective was to estimate the risk of redo valve surgery and 10-year survival after valve replacement performed using either suture technique.

METHODS

Patients who underwent mechanical AVR or MVR using a St. Jude prosthesis between December 1991 and June 1997 were included. Eighteen patients had MVR and 43 had AVR using IN sutures; 49 and 83 patients received MVR and AVR, respectively, using SC sutures. The majority of these patients were part of a randomized controlled trial with different end points, presented elsewhere. Patients were followed for 10 years with annual transthoracic echocardiography, and clinical data were collected retrospectively. Kaplan-Meier survival analysis was performed. Cox's regression analysis was performed to identify factors predicting mortality as a function of time. Forward stepwise logistic regression was performed to analyze risk factors predicting PPR. Mann-Whitney U test was used for continuous and nonparametric data, and chi2 test and Fisher's exact test were used for categorical data. A probability value less than 0.05 was considered significant.

RESULTS

The overall risk of PPR after MVR and AVR was higher in the SC group than in the IN group. The need for redo AVR was significantly higher in the SC group. The suture technique did not affect the 10-year survival after either AVR or MVR.

CONCLUSIONS

Use of SC technique increases the risk of significant PPR after AVR and MVR compared with IN technique independent of the size of prosthesis, degree of annular calcification, disease of the excised valve, or the implanting surgeon. Although 10-year survival is independent of suture technique, SC technique increases the risk of redo valve replacement after AVR.

Hemolysis associated with prosthetic heart valves: a review

Hemolysis is one of the potentially serious complications of prosthetic heart valves. It is usually associated with either structural deterioration or paravalvular leak. Mild, compensated hemolysis associated with mechanical heart valves is not uncommon even in the current era. Severe hemolysis is rare, however, and usually reflects paravalvular leak. The use of transesophageal echocardiography-guided operative techniques may help prevent or minimize early postoperative paravalvular leakage. There is a gamut of available therapeutic approaches-medical, transcatheter, and surgical-to this complication and therapy should be tailored to the individual patient. Novel pharmacological agents include erythropoietin and pentoxifylline. Several reports described the feasibility of transcatheter closure of paravalvular leak with coils or devices, but their effect on hemolysis is unpredictable. Surgery remains the treatment of choice in severe cases.

Evaluation of hemolysis in patients with prosthetic heart valves

The primary mechanism and most common cause of hemolytic disease in patients with prosthetic heart valves are mechanical trauma to red blood cells and paraprosthetic valvular regurgitation, respectively. Presenting features in patients with this condition include anemia, congestive heart failure, fatigue, jaundice, dark urine, and a regurgitant murmur. Various laboratory studies can be utilized to diagnose hemolytic anemia and to assess the severity of hemolysis. Transthoracic echocardiography, transesophageal echocardiography, and Doppler studies including color Doppler are useful imaging methods to assess valve function. Treatment is usually medical (oral iron); however, in patients with paravalvular regurgitation, surgery is often required to correct the anemia.

Prevalence and clinical significance of incidental paraprosthetic valvar regurgitation: a prospective study using transoesophageal echocardiography

OBJECTIVE

To assess the prevalence, mechanisms, and significance of paraprosthetic regurgitation detected incidentally by transoesophageal echocardiography (TOE) in patients after heart valve replacement.

DESIGN

Prospective observational study.

SETTING

Tertiary referral centre.

PATIENTS

360 consecutive patients (mean (SD) age 65.8(9.5) years, 193 women) undergoing elective first ever valve replacement.

METHODS

Postoperative and follow up TOE, and tests for haemolysis and anaemia.

RESULTS

There were 243 aortic, 90 mitral, and 27 double valve replacements, using 316 mechanical and 44 tissue valves, giving 270 aortic and 117 mitral valves. One patient with severe paraprosthetic mitral regurgitation underwent immediate reoperation and was excluded from subsequent analyses. Paraprosthetic jets were detected around 16 (6%) of the aortic and 38 (32%) of the mitral valves (p < 0.05) at the postoperative study. Follow up TOE was available for 151 aortic and 67 mitral valves, 0.9 (0.5) years after operation. Paraprosthetic jets were present in 15 (10%) of the aortic and 10 (15%) of the mitral valves (NS). Two thirds of the aortic and a fifth of the mitral jets were new. Paraprosthetic jets were more common in aortic valves in a supra-annular (12 of 88, 14%) than in an intra-annular position (4 or 182, 2%; p < 0.005) and in mitral valves inserted with continuous (36 of 88, 41%) rather than interrupted sutures (2 of 28, 7%; p < 0.001). Lactate dehydrogenase concentration was higher in patients with paraprosthetic jets than in those without (752 (236) v 654 (208) IU/l, p < 0.001). Haemoglobin and haptoglobin concentrations were not different.

CONCLUSIONS

Small paraprosthetic leaks are common, are related to surgical factors, are not associated with increased subclinical haemolysis, and are benign during the first year after heart valve replacement.

Intravascular hemolysis in patients with new-generation prosthetic heart valves: a prospective study

OBJECTIVE

A prospective clinical study was designed to assess the frequency and severity of intravascular hemolysis in patients with new-generation, normally functioning prosthetic heart valves.

METHODS

Hemolysis was evaluated in 172 patients with a mechanical prosthesis (53 CarboMedics and 119 Sorin Bicarbon) and in 106 patients with a bioprosthesis (15 St Jude Medical Toronto, 19 Baxter Perimount, and 72 Medtronic Mosaic) in the aortic position, mitral position, or both. Aortic valve replacement was performed in 206 patients, mitral valve replacement in 59 patients, and double valve replacement in 13 patients. The presence of hemolysis was assessed on the basis of the level of serum lactic dehydrogenase and serum haptoglobin and the presence and amount of reticulocytes and schistocytes in the peripheral blood. Severity of intravascular hemolysis was estimated on the basis of serum lactic dehydrogenase. Clinical, echocardiographic, and hematologic evaluations were performed 1, 6, and 12 months after discharge.

RESULTS

None of the 278 patients experienced decompensated anemia, whereas at 12 months, mild subclinical hemolysis was identified in 49 patients, 44 (26%) with a mechanical prosthesis and 5 (5%) with a bioprosthesis (P <.001). At multivariate analysis, independent predictors of the presence of subclinical hemolysis were mitral valve replacement (P <.001), use of a mechanical prosthesis (P =.002), and double valve replacement (P =.02). Frequency of hemolysis in patients with stented aortic bioprostheses was 3%, whereas it was absent in those with stentless valves. Among mechanical valve recipients, double versus single valve replacement (P =.04) and mitral versus aortic valve replacement (P =.05) were correlated with the presence of hemolysis; double valve recipients also showed a more severe degree of hemolysis (P =.03). In patients with a Sorin Bicarbon prosthesis, hemolysis was less frequent (22% vs 34%, P =.09) and severe (P <.001) than in those with a CarboMedics prosthesis.

CONCLUSIONS

In normally functioning prosthetic heart valves, subclinical hemolysis is a frequent finding. A low incidence of hemolysis is found in stented biologic prostheses, and it is absent in stentless aortic valves. Modifications of valve design may contribute to minimize the occurrence of hemolysis in mechanical prostheses.

Direct right ventricular puncture for hemodynamic evaluation of a mechanical tricuspid valve prosthesis: a new indication for an old procedure

The advent of transvenous right heart catheterization has relegated direct transthoracic right ventricular puncture largely to the role of "interesting historical footnote." However, in the case of a right ventricle that is "protected" by a mechanical tricuspid valve prosthesis, direct right ventricular puncture represents a reasonable alternative for obtaining accurate hemodynamic information.

Echocardiography and Doppler assessment of prosthetic heart valves with transesophageal echocardiography

This article examines the use of transesophageal echocardiography (TEE) in the assessment of prosthetic heart valves. A summary of the commonly used artificial valves and their physiologic regurgitant flow patterns, as identified by color Doppler imaging, is presented. The hemodynamic evaluation of prosthetic valve stenosis using Doppler techniques is reviewed, and the diagnostic utility of TEE in identifying the complications of cardiac prostheses is discussed.

Thrombosed prosthetic valve in tricuspid position. Successful therapy with intravenous streptokinase

The successful use of streptokinase therapy in a child with chronic thrombosis of a prosthetic valve (Carbomedics) in the tricuspid position is presented.

Streptokinase treatment of a thrombosed Björk-Shiley prosthesis in the aortic position

Dysfunction of a mechanical prosthetic valve caused by thrombus formation is usually treated surgically. A patient with a thrombosed Björk-Shiley valve in the aortic position was treated successfully with intravenous streptokinase. The considerable improvement in the patient's clinical condition and the phonocardiographic, echocardiographic, and cinefluoroscopic evidence of normalisation of prosthetic valve function established the efficacy of thrombolytic therapy of a thrombosed prosthetic valve in this patient.

Severe haemolytic anaemia after replacement of the mitral valve by a St Jude medical prosthesis

Severe haemolytic anaemia developed in a 33 year old patient after the mitral valve was replaced with a St Jude medical prosthesis. This was the patient's third thoracotomy. She had already had a mitral commissurotomy and a mitral valve bioprosthesis. The patient had an E+ antibody to red blood cells as well as a paraprosthetic leak. The haemolysis became less severe once the population of E+ red cells was completely haemolysed. However, the patient continued to require transfusions to remain out of heart failure. Once the valve was replaced, the haemolysis subsided. Fulminant haemolysis after mitral valve replacement is rare. When it does occur, a paraprosthetic leak should be suspected. Other causes of haemolysis, however, must also be considered and these may contribute to the severity of haemolysis.

Hospital survey of antimicrobial prophylaxis to prevent endocarditis in patients with prosthetic heart valves

The American Heart Association (AHA) has published guidelines for use of prophylactic antibiotics to prevent bacterial endocarditis, but few data are available about physician compliance with these guidelines. A retrospective review was conducted of the use of prophylactic antibiotics in patients with prosthetic heart valves who were undergoing diagnostic or operative procedures or heart catheterization at three hospitals. Compliance with AHA recommendations was only 30 percent (14 of 46) for procedures considered high risk for patients with prosthetic heart valves. Six (23 percent) of 26 patients who underwent right or left heart catheterization received prophylactic antibiotics (not recommended by AHA). Antibiotics were given to 42 (74 percent) of 57 patients who underwent surgical procedures considered at low risk of bacteremia, but only 33 (58 percent) received antibiotics that cover organisms commonly present at the site of the procedure. The results indicate that clinicians frequently do not administer prophylactic antibiotics in patients with prosthetic heart valves who are undergoing invasive procedures or do not follow published AHA guidelines when antibiotics are administered.

A practical approach to prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) is an infrequent but dread complication, occurring in 1 to 2% of patients both early (less than 60 days) and late postoperatively. Diagnosis is always (99%) possible by two sets of blood cultures, but occasional exogenous causes of bacteremia may cloud the diagnosis, as will culture-negative cases of PVE and skin contaminants. With obvious exogenous sources of bacteremia, achieving sterile blood cultures after eradication of the noncardiac source permits discontinuation of antibiotics after two weeks. When skin contaminants are suspected, withholding antibiotics and obtaining two sets of blood cultures is recommended, because the bacteremia with PVE is continuous. Preventive measures, including perioperative antibiotics, are warranted but will probably not significantly reduce the low incidence of infection already achieved. The major cause of improved survival in recent years is earlier operation (valve rereplacement). This has been demonstrated in the last ten years and is absolutely indicated for major heart failure, ongoing sepsis, fungous etiology, valve obstruction, new-onset heart block, and unstable prosthesis by fluoroscopy.

Acute thrombotic obstruction with disc valve prostheses: diagnostic considerations and fibrinolytic treatment

Twenty-six patients presenting with 28 instances of massive acute thrombotic obstruction of a prosthetic valve (16 mitral, 12 aortic) were treated with fibrinolytic agents. In 15 cases the patient presented with acute pulmonary edema and low cardiac output, in 10 with congestive heart failure and embolism and in 3 with peripheral embolism only. The diagnosis of thrombotic obstruction was made by echocardiography or cineradiography, in patients in whom the disc was immobile or barely moving; cineangiography was necessary in only four patients. The fibrinolytic agents administered were streptokinase, 2,000,000 U for 10 hours (14 cases), urokinase, 4,500 U/kg per h for 12 hours (7 cases), or the two agents successively (7 cases). Fibrinolysis was entirely successful in 19 patients: 18 are alive and well without surgical intervention after follow-up of 6 to 64 months and 1 patient had surgical revision after fibrinolysis. In two patients, fibrinolytic treatment was apparently successful but obstruction recurred 4 and 19 months later, respectively, and the patients were again treated by fibrinolysis. In two patients complete failure of fibrinolytic treatment led to emergency surgery, and in three patients improvement was incomplete and death occurred shortly after treatment. No hemorrhagic complications were observed, but there were five cases of embolism during the fibrinolytic treatment. Fibrinolytic treatment would seem to be an attractive, nonsurgical alternative for the thrombosis of a valve prosthesis but, because of the risk of embolism with possible permanent damage, its use should be reserved for critically ill patients who are too sick to undergo immediate surgery.

Echo-phonocardiographic evaluation of the Björk-Shiley mitral prosthesis

Ninety patients were studied with combined echophonocardiography after Björk-Shiley disc prosthetic mitral valve replacement. They were evaluated every 6 months (mean follow-up 6 years). Nine cases of left ventricular (LV) failure and 6 cases of prosthetic malfunction (5 paravalvular leaks and 1 thrombosis) were detected; 1 case was confirmed at necropsy and the other 5 cases were surgically verified and repaired. The following measures of prosthetic malfunction were evaluated: opening and closing velocity, maximal amplitude of the prosthesis, septal motion 6 months after operation, LV diastolic diameter, protodiastolic hump, variations during same record of the interval between aortic valve closure sound to the phono and mitral valve opening to the echo, and interval between aortic valve closure sound and maximal excursion of the LV posterior wall. All measures studied were useful for detecting prosthetic malfunction, but 2 are more useful in individual cases: variations of the interval between second heart sound and mitral valve opening and the interval between the aortic valve closure sound and LV posterior wall motion. These 2 intervals also allow discrimination between normal function, prosthetic malfunction and LV failure.

Post-cardiac injury syndrome and an increased humoral immune response against the major contractile proteins (actin and myosin)

To better understand the pathogenesis of the post-cardiac injury syndrome (PCIS) 2 models of cardiac injury were studied. One hundred twenty-nine patients who underwent cardiac surgery and 80 patients with acute myocardial infarction (AMI) were prospectively followed and the levels of anti-heart antibodies (AHA), anti-actin antibodies (AAA) and anti-myosin antibodies (AMA) were determined. In the surgical group, PCIS developed in 27 patients (21%) and incomplete PCIS in 36 (28%). In the AMI group, PCIS did not develop in any patient, but incomplete PCIS developed in 11 patients (14%) (p less than 0.001). The surgical group showed a significantly higher humoral immune response than the AMI group when analyzed for AHA and anti-contractile protein antibodies. After cardiac surgery, AHA developed in 59 patients (46%), AAA developed in 33 (26%) and AMA developed in 49 (38%); in the AMI group, significant levels of AHA, AAA and AMA developed in 16 (20%), 7 (9%) and 13 patients (16%), respectively. These studies show a significant correlation between the PCIS clinical classification and auto-antibodies raised against heart contractile proteins.

Prosthetic valve endocarditis developing after an infected scalp laceration

This case report describes a 21-year-old man who developed prosthetic valve endocarditis (PVE) from an infected scalp laceration. Despite intravenous antibiotic therapy, the infectious process could not be controlled and the patient required replacement of the aortic valve. Our patient is the fourth case of late PVE occurring after a subcutaneous infection. In each case, antibiotic prophylaxis of infective endocarditis was not practiced. Current antibiotic regimens for prophylaxis of PVE are reviewed.

Thrombotic obstruction of Bjork-Shiley valves--diagnostic and surgical considerations

We have evaluated 12 patients with thrombotic obstruction of the Bjork-Shiley valve since 1975, 11 in the mitral and 1 in the aortic position. During this period 442 patients with 303 mitral (181 plano-convex and 122 convexo-concave) and 205 aortic (112 plano-convex and 93 convexo-concave) Bjork-Shiley valves were available for follow-up. The incidence of thrombosis for the plano-convex model was 1.06% per patient year for the mitral position and 0.19% per patient year for the aortic position. The new convexo-concave model has brought down the incidence to 0.78% per patient year for the mitral (P less than 0.01) and 0% per patient year for the aortic valve. The onset of symptoms was acute (less than 15 days) in 41.7% and subacute (greater than 15 days) in 58.3% patients. All patients presented with pulmonary edema. Evidence of inadequate anticoagulation was present in only 3 (25%) patients. Reduction of prosthetic sounds and appearance of a new murmur was highly suggestive of valve thrombosis. Echocardiography and cinefluoroscopy was very useful for the instant recognition of this condition and had obviated the need for cardiac catheterisation in the last 6 patients. Emergency surgery was obligatory in all. Thrombectomy alone was successful in 9 patients. Three patients required replacement of the prosthesis. There was one operative death (mortality 8.3%). The long-term follow-up of these patients (3-82 months, mean 34 months) is excellent. We conclude that thrombotic obstruction of the Bjork-Shiley valve is often not related to inadequate anticoagulation, and more than half of the patients do not present with abrupt onset of symptoms. The convexo-concave model has significantly reduced this problem. Emergency surgery with thrombectomy is the procedure of choice for clotted prostheses.

Streptokinase thrombolysis of a chronically thrombosed mitral prosthetic valve

Thrombus obstruction of a prosthetic heart valve is usually treated surgically. We report a well-documented case of an obstructed mitral prosthetic valve where fibrinolytic treatment was successful. Furthermore the thrombus formation probably had occurred 6 months earlier. Thus fibrinolysis appears to be a safe alternative to surgery although late occurrence of thrombosis may be possible.

Prosthetic heart valves: a review

There are a number of difficulties inherent in the analysis of such a large and diverse quantity of data. In a substantial number of clinical trials, there is no significant effort made to evaluate prosthetic performance as a function of preoperative cardiac anatomy. Hemodynamics have not been systematically studied in relation to preexisting left ventricular size, shape, or configuration, mitral annular orientation, or left atrial size. Postoperative anticoagulation protocols vary from one institution to another and occasionally within study groups themselves. Less tangible variables such as alteration in surgical technique over time and differential familiarity of cardiovascular surgeons with the prostheses employed are chronic problems in any study of this sort. Perhaps the greatest variable in evaluating the postoperative performance of valvular prostheses over the past 20 yr is the radical improvement in techniques of intraoperative myocardial preservation. Notwithstanding, comparisons are possible within the confines of certain criteria. The caged ball value remains in use after 20 years of clinical experience. It has sustained the greatest number of modifications, probably because it has been the most extensively studied. Hemodynamics are adequate although its centrally obstructed design is responsible for increased turbulence, hemolysis, and neointimal proliferation, particularly in the aortic position. The device has been shown to be durable with virtually no reports of ball variance since the alteration of the silicone curing procedure in 1965. Thromboembolic rates are acceptable in the anticoagulated patient while prosthetic thrombosis is not a grave threat in the non-close clearance device. Incidence of endocarditis is not particularly different from that associated with all nonbioprosthetic valves, although there is a much greater published volume of clinical experience concerning recognition and treatment of late prosthetic valve endocarditis in patients with caged ball valves than there is for any other replacement device. Perhaps the most serious disadvantage to caged ball design is its size. Its large spatial requirements have led to anatomic complications in patients with small aortic roots, isolated mitral stenosis, left ventricular hypertrophy, and double valve replacement, among others. Nevertheless, this is still the valve of choice in some centers.(ABSTRACT TRUNCATED AT 400 WORDS)

Indexes of intravascular hemolysis, quantification of coagulation factors, and platelet survival in patients with porcine heterograft valves

Ten patients with porcine heterograft valves who were not receiving anticoagulant agents were evaluated to determine the effect of the valve on red blood cell survival and on platelet activation and consumption as measured by (1) quantification of the coagulation mechanism, (2) platelet function studies, and (3) 51-chromium platelet survival time. There was no evidence of significant intravascular hemolysis as determined by the reticulocyte count, serum iron and iron binding capacity, serum bilirubin level, or lactic dehydrogenase activity. The coagulation profile and the platelet function studies were normal. No statistically significant difference was found in the platelet survival time in the 10 patients with porcine heterograft valves (half-life 3.2 +/- 0.8 days) and the 11 normal control subjects (half-life 3.6 +/- 0.6 days) (p greater than 0.2). The finding of a normal platelet survival time in patients with porcine heterograft valves is consistent with clinical experience indicating that this device is associated with a low incidence of systemic embolization, approximating 3% per year.

Paroxysmal hypotension associated with sympathetic withdrawal. A new disorder of autonomic vasomotor regulation

We evaluated a patient who had transient episodes of hypotension with clinical and laboratory features apparently distinct from previously recognized disorders of vasomotor regulation. In between his abrupt attacks of hypotension, the patient is asymptomatic and demonstrates normal autonomic modulation of heart rate and blood pressure in response to changes in body position, Valsalva maneuver, cold, and exercise. During periods of hypotension, his plasma norepinephrine falls markedly and he has blunted or absent responses to stimuli that normally have a pressor effect due to sympathetic efferent discharge. Mechanical or known hormonal disorders that produce episodic hypotension have been excluded by extensive testing. We suggest two possible causes for our patient's paroxysmal sympathetic withdrawal: first, a centrally mediated inhibition of sympathetic discharge to peripheral resistance and capacitance vessels, but with no afferent stimulus reflexly producing sympathetic withdrawal readily evident; or second, an episodic release of an unknown endogenous compound with inhibitory effects upon central or preganglionic sympathetic neurons or upon postganglionic sympathetic neurons by a presynaptic inhibition of norepinephrine release.

Björk-Shiley mitral valvular dehiscence. Documented by radiography, echocardiography, fluoroscopy, and cineangiography

This case report presents combined radiographic, echocardiographic, fluoroscopic, and cineangiographic findings of the dehiscence of a Bjork-Shiley mitral prosthetic valve. The valvular dehiscence was confirmed at surgery. A distinct rounding of the opening phase of the valve was recorded on the echocardiogram. Other clinical evidence, documenting the severe valvular dehiscence, is reported in detail. Non-invasive procedures are therefore invaluable in recording prosthetic valvular dysfunction.

Long-term clinical and hemodynamic evaluation of the Ionescu-Shiley pericardial xenograft heart valve

Pericardial xenograft heart valves have been used in 469 patients for single or multiple valve replacement. Early in the series, valves were made in-house, but since May 1976, valves have been made by Shiley Laboratories, Inc. During the eight-year observation period, there were 7% early and 7.9% late deaths. Although no anti-coagulants were used on a long-term basis, there were only eight mild embolic episodes. Preoperatively, 56--98% of all patients were in class III or IV of the NYHA classification; postoperatively, all surviving patients have been found to have improved by at least one classification.

Hemodynamic evaluation of patients with combined mitral and aortic prostheses

Complete hemodynamic evaluation of patients with combined aortic and mitral mechanical valve prostheses presents a difficult technical problem. Yet such patients with cardiac symptoms postoperatively often require this evaluation to determine the diagnosis and the advisability of reoperation. A 4 year experience with 22 patients requiring such evaluation is reviewed. Eight patients (36 percent) required reoperation for malfunction of the prosthesis. Four (18 percent) had major complications of the cardiac catheterization study, but no fatalities or residual permanent defects resulted. In 17 cases transthoracic left ventricular needle entry was used. A standardized procedure of this type for both pressure measurement and angiographic studies has evolved, providing reasonable efficiency and a relative degree of safety. The patient is positioned in the right anterior oblique position for optimal needle entry into the left ventricular apex and angiographic visualization of mitral prosthetic incompetence and the myocardial contractile pattern. A 16 gauge needle with side holes but no end hole allows ventriculography to be performed after chamber entry using the prostheses as reference points under fluoroscopic guidance. Retrograde catheterization of the aortic prosthesis, transseptal left atrial catheterization with anterograde crossing of the mitral prosthesis and transapical pressure measurement with a similar needle, combined with quantitative left atrial angiography, are alternative choices for study.

Surgical management of left ventricular-aortic discontinuity complicating bacterial endocarditis

Successful hemodynamic repair of left ventricular-aortic discontinuity complicating bacterial endocarditis in 2 patients was achieved using a composite valve-woven Dacron tube graft. The prosthetic valve was sutured without tension into the remaining aortic annulus, ventricular muscle, and base of the aortic leaflet of the mitral valve. Use of the composite graft allows adequate debridement of the abscess, restores ventricular-aortic continuity, excludes the abscess wall from systemic pressure, and does not require saphenous vein coronary bypass. Total exclusion of the aortic root, as described, is a lifesaving alternative repair in the care of desperately ill patients with this condition.

A collaborative study of infective endocarditis in the 1970s. Emphasis on infections in patients who have undergone cardiovascular surgery

Twenty-six major cardiovascular centers participated in a cooperative study of all cases of infective endocarditis occurring during a single calendar year to obtain an overview of infective endocarditis. The study was designed to learn which patients appear to be at highest risk to develop this infection after palliative or reparative cardiovascular surgery. Of 278 patients developing infective endocarditis during the year at these medical centers, 63 (23%) had had previous cardiovascular surgery and 215 had not. Seventy percent of the 278 patients had recognized congenital or acquired heart disease before developing the infection. Rheumatic heart disease accounted for over half of the patients with underlying structural heart disease. A majority (55%) of the 63 patients who had been operated on before developing endocarditis had prosthetic valves inserted. Of those who did not require prosthetic valves, the majority had congenital heart disease with systemic artery-to-pulmonary artery shunts. Although these data were obtained from a selected group of patients, they confirm a significant risk of endocarditis in patients with prosthetic valves and suggest that in postoperative patients with non-valvular congenital heart disease, the highest risk appears to be in cyanotic patients with palliative pulmonary artery-to-systemic artery shunts.

Complications due to cloth wear in cloth-covered Starr-Edwards aortic and mitral valve prostheses--and their management

Five cases of complications due to cloth wear in cloth-covered composite-seat Starr-Edwards aortic and mitral valvular prostheses are described. The complications of cloth wear were recurrent systemic emboli in three patients, two with aortic and one with mitral prosthesis, and severe hemolytic anemia in two patients with aortic prosthesis. The over-all incidence of clinically significant complications due to cloth wear in aortic and mitral valve prosthesis was 2.5 per cent. The diagnosis of cloth wear is impossible before reoperation and it was made by exclusion of other causes of recurrent transient cerebral ischemic attacks or systemic emboli and by exclusion of other causes of hemolytic anemia. Clinical and laboratory findings suggestive of cloth wear are described. Aggressive management of complications of cloth wear by reoperation is likely to prevent disabling or lethal consequences. Porcine xenograft aortic and mitral bioprostheses were used in these patients to replace the cloth-covered valvular prostheses. The symptoms due to cloth wear were abolished in all patients by reoperation, and all patients are off anticoagulants postoperatively. The operative mortality rate for reoperation in this small group of patients was zero.

Anticoagulant therapy and central nervous system complications in patients with prosthetic valve endocarditis

Among 52 cases of prosthetic valve endocarditis, adequate anticoagulant therapy was administered in 38 and discontinued or given in subtherapeutic dosage in 14. Our data suggest that anticoagulant therapy does not appreciably increase morbidity or mortality in patients with prosthetic valve endocarditis. On the contrary, in our patients the incidence of major clinical CNS (central nervous system) complications was increased and the mortality was higher if anticoagulant therapy was discontinued. CNS complications occurred in 10 of the 14 patients without adequate anticoagulant therapy and in three of the 38 with adequate anticoagulant therapy. Mortality was 57% among those treated without adequate anticoagulation and 47% among those with adequate anticoagulation. At autopsy, CNS complications were thought to be the primary cause of five of the eight deaths in cases without adequate anticoagulation.

Cephalothin induced neutropenia during the treatment of bacterial endocarditis

The occurrence of cephalothin induced neutropenia in 3 patients with infective endocarditis is described. In each patient, withdrawal of cephalothin was followed by rapid haematological recovery. It is apparent that granulocytopenia may frequently occur in patients receiving prolonged, high dose, intravenous cephalothin for the treatment of bacterial endocarditis.

Intracranial hemorrhage and infarction in anticoagulated patients with prosthetic heart valves

In 1 year 6 patients with prosthetic heart valves (PHVs) treated with anticoagulants suffered intracranial hemorrhage. In 4, hemorrhage occurred into the site of a recent non-hemorrhagic infarction. In the others, both of whom had endocarditis, hemorrhages probably occurred as the result of rupture of a mycotic aneurysm. Five patients were treated with warfarin, 1 with heparin. In all patients the level of anticoagulant activity was greater than 1.5 times control. Five patients were in atrial fibrillation; 1 was hypertensive. The diagnosis of intracranial hemorrhage was made and its location and extent accurately determined by computed tomography (CT). Three patients underwent surgery and 2 are alive with only minor neurological deficits. Among the 3 patients who did not undergo surgery 2 died and 1 is alive with a moderate neurological deficit. The management of PHV patients with use of anticoagulants is discussed in terms of the mechanisms involved in intracranial bleeding. Emphasis is placed on prevention of emboli, discontinuation of anticoagulants once non-hemorrhagic infarction has occurred and the primacy of CT scan in diagnosis when hemorrhage is suspected. The special problems of anticoagulation in the presence of endocarditis are also discussed.

Prosthetic valve endocarditis: reviewing the problem

Bacterial endocarditis is a serious complication of valve replacement, with an overall mortality of 59%. Fever, although a constant feature of the condition, is a nonspecific finding; other manifestations may or may not be present and the diagnosis may be overlooked. Any patient with a prosthetic heart valve and bacteremia should be considered to have endocarditis and should be treated accordingly.