Patients Undergoing Heart Valve Replacement Research Articles

Cardioprotective Effects of Electroacupuncture Pretreatment on Patients Undergoing Heart Valve Replacement Surgery: A Randomized Controlled Trial

Cardiac ischemia-reperfusion injury after cardiopulmonary bypass contributes to postoperative morbidity and mortality in patients with open-heart surgery. This randomized controlled trial was designed to address the protective effects of electroacupuncture (EA) pretreatment on myocardial injury in patients undergoing heart valve replacement surgery. Sixty patients with acquired heart valve disease were randomly allocated to the EA pretreatment group or the control group. Patients in the EA group received EA stimulus at bilateral Neiguan (PC 6), Lieque (LU 7), and Yunmen (LU 2) for 30 minutes each day for five consecutive days before surgery. Hemodynamic data, mechanical ventilation time, inotropic drug use in the intensive care unit, serum cardiac troponin I concentrations, morbidities, and mortalities were compared between the two groups. This trial is registered with ClinicalTrials.gov, number NCT00732459. At 6 hours, 12 hours, and 24 hours after reperfusion, levels of serum cardiac troponin I were significantly decreased in the EA group (5.74 +/- 0.67, 6.22 +/- 0.66, and 5.21 +/- 0.58) compared with that in the control group (7.89 +/- 0.74, 8.34 +/- 1.08, and 7.57 +/- 0.89, p < 0.05). The EA pretreatment significantly reduced overall serum troponin I release at 6 hours, 12 hours, and 24 hours after aortic cross-clamp removal. Meanwhile, EA pretreatment also reduced the inotrope score at 12 hours, 24 hours, and 48 hours after the intensive care unit arrival and shortened intensive care unit stay time (p < 0.05). The present study demonstrated that EA pretreatment may alleviate cardiac ischemia-reperfusion injury in adult patients undergoing heart valve replacements. This simple and convenient treatment has the potential to be used in the clinic for reducing myocardial injury in patients with heart valve replacement surgery.

Postconditioning the Human Heart with Adenosine in Heart Valve Replacement Surgery

The effect of adenosine postconditioning on myocardial protection in cardiac surgery remains uncertain. The present study evaluated the safety, feasibility, and beneficial effect of adenosine postconditioning as an adjunct to predominantly used cold-blood cardioplegic myocardial protection method in the setting of heart valve replacement operations. Sixty patients with rheumatic heart valve disease undergoing heart valve replacement operations were randomized to an adenosine (1.5 mg/kg) or saline (as control) bolus injection through an arterial catheter immediately after the aorta cross-clamp was removed. The surgical indications were similar in both groups, and heart valve replacement was successful in all patients. The extubation time and postoperative hospital time were similar in both groups. Compared with the control group, however, the inotrope scores in the intensive care unit (ICU) were much lower (p < 0.01), and the ICU time was significantly shorter (p < 0.05) in adenosine group. More important, cardiac troponin I release was less in the adenosine group, especially at 12 and 24 hours after reperfusion (p < 0.01), and total cardiac troponin I release estimated with the area under curve was also significantly reduced during the first 24 hours after reperfusion (p < 0.01). A 1.5-mg/kg bolus administration of adenosine through an arterial catheter immediately after the aorta cross-clamp is removed is feasible and well tolerated in patients undergoing heart valve replacement. An adenosine postconditioning adjunct to high potassium cold blood myocardial protection is related to less troponin I release, less inotropic drug use, and shorter ICU stay.

CT05 MECHANICAL VALVE OR TISSUE VALVE: DO PATIENTS REGRET THEIR DECISION?

Purpose Patients undergoing heart valve replacement are usually given a choice of valve type, mechanical or tissue. Each of these broad valve types has basic advantages and disadvantages which are discussed with the patient pre‐operatively, allowing them to make their decision. Post‐operatively patients have a variety of experiences, related to the valve itself, complications of the operation, and other co‐morbidities. The aim of this study was to determine patient satisfaction with the type of valve they chose, and whether they would have changed their mind given their experience.Methodology A one page postal survey with multiple choice questions was sent to 350 patients identified on the hospital database who had undergone cardiac valve replacement. The data obtained was compared to database information and analysed.Results Patients reported a variety of experiences following their discharge from hospital, from thrombo‐embolic events, arrhythmias, bruising and bleeding and ongoing warfarin dosing difficulties. Very few patients (&lt;0.5%) stated that given their experience would have chosen a different type of valve. Also few patients (&lt;5%) who received biological valve replacements ended up requiring warfarin long term.Conclusions Despite many patients having significant problems post‐operatively, very few regret their choice of valve type.

Effect of L-carnitine on cardiomyocyte apoptosis and cardiac function in patients undergoing heart valve replacement operation

The effects of L-carnitine, as an ingredient of cardioplegia solution, on cardiac function and cardiomyocyte apoptosis in patients undergoing heart valve replacement operation were investigated. Twenty-three cases undergoing heart valve replacement with cardiopulmonary bypass (CPB) were randomly allocated into two groups: L-carnitine group (n = 12, 12 g/L L-carnitine was put in the ST. Thomas cardioplegia) and control group (n = 11, identical to the L-carnitine group except that normal saline was administered instead of L-carnitine). Serum cardial troponin I (cTnI) levels, the left ventricular ejection fraction (LVEF), and cardiac index (CI) were measured perioperatively. A bit of myocardial tissue obtained from right atria was taken before CPB and by the end of intracardiac procedure to undergo electron microscopy examination and estimate apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). From the end of CPB to 3 days after operation, the serum levels of cTnI in the L-carnitine group was significantly lower than that in the control group (P < 0.05). Heart color ultrasonogram showed that the CI index and LVEF at 7th day postoperatively in the L-carnitine group were significantly higher than in the control group (P < 0.05). Compared to the control group, L-carnitine significantly alleviated the morphologic changes of cardiac muscle cells (electron microscopy examination) and decreased the amounts of apoptotic cardiac muscle cells (TUNEL). Furthermore, the dosage of vasoactive drugs used after operation was significantly less in the L-carnitine group (P < 0.01). It was concluded that L-carnitine cardioplegia solution could improve cardiac function in patients undergoing heart valve replacement operation and alleviate CPB-mediated apoptosis of cardiac muscle cells.

Outcomes in nonagenarians after heart valve replacement operation

Background Changes in the age profile of the United Kingdom population and improvements in preoperative and postoperative care have resulted in increasing numbers of very elderly patients undergoing heart valve replacement (HVR) operations. Although HVR operations in nonagenarians are relatively uncommon, the demand for cardiac operations in this age group may increase over time. Outcomes after HVR operations in nonagenarians have not been well described yet. Therefore, the aim of this study was to determine outcomes in terms of early mortality and long-term survival in 35 nonagenarians after HVR operation. Methods Data from the United Kingdom Heart Valve Registry were analyzed and nonagenarian patients were identified. Additional analyzed data include gender, valve position, valve type, valve size, operative priority, follow-up time, and date and cause of death. Kaplan-Meier actuarial curves were calculated to determine accurate 30-day mortality and long-term survival. Results On average five HVR operations are performed annually in the United Kingdom in nonagenarians with equal numbers of males and females. Aortic valve replacement with a bioprosthetic valve was the most common operation and 86% were elective admissions. Fourteen patients died within the review period; mean time to death was 402 days. Overall 30-day mortality was 17%, which was higher for males compared with females; females also displayed better long-term survival. Conclusions HVR operations in nonagenarians carry a significantly higher risk of early mortality and reduced long-term survival. Despite increases in the age profile of the population, elective HVR operation with patients aged 90 years or older is likely to remain an infrequent surgical procedure reserved for very carefully selected patients.

Use of prothrombin fragment 1+2 for evaluating anticoagulant therapy after mechanical heart valve replacement

Prothrombin fragment 1+2 (F1+2) is a coagulation factor newly used as a molecular marker to monitor anticoagulant therapy in patients undergoing heart valve replacement. We evaluated the usefulness of F1+2 against that of prothrombin time (PT) reported as the internationalized normalized ratio (INR) in 93 patients undergoing mechanical heart valve implantation between August 1999 and July 2000. The study group consisted of 38 men and 55 women, with an average age of 61.1±11.2 years. The surgeries were 34 aortic replacements, 9 double valve replacements, and 50 mitral valve replacements. Warfarin doses were controlled based on PT-INR values at a target range of 1.5–2.5 F1+2 levels in the 0.4–1.2 nmol/l level were considered normal. No thromboembolism or bleeding complication occurred in any patient during the mean follow-up period of 12 months. The overall correction coefficient between F1+2 and PT-INR was 0.165 (P 2.50 were less than half of the lower limit of normal. Our analysis involving F1+2 confirmed PT-INR in the 1.5–2.5 range following mechanical heart valve implantation to be optimal. We found that using F1+2 to monitor individual response to anticoagulation therapy is useful when PT-INR values are difficult to obtain.

Cohort survey of heart valve replacement patients: does the valve card scheme have room for improvement?

Patients undergoing heart valve replacement have a high risk of experiencing valve related adverse events such as acute failure of the valve mechanism, valve thrombosis, and peripheral emboli. Immediate availability...

Ten-year trends in heart valve replacement operations

Background. There has been increasing concern in recent years about the quality and cost of heart valvular replacement procedures. The purpose of this study is to examine the profile of patients undergoing valvular operations during the past decade, and to look at trends in outcome and resource utilization over that period. Methods. Clinical and procedural data of 2,972 patients undergoing heart valve replacement at Emory University Hospitals between 1988 and 1997 were recorded prospectively on standardized forms by trained medical personnel and entered into a computerized database. Results. There were 1,802 patients undergoing aortic valve replacement (AVR), 966 undergoing mitral valve replacement (MVR), and 204 undergoing combined aortic and mitral valve procedures (AVR + MVR). No patients were excluded. There was a statistically significant trend for patients undergoing AVR, MVR, or AVR + MVR over time to be older and sicker by multiple criteria. Nonetheless, procedural outcome and in-hospital mortality for patients undergoing AVR remained unchanged. Cost and length of stay increased from 1988 to 1992 when a concerted effort to decrease resource utilization began. Between 1992 and 1997 for AVR, length of stay decreased from 13.4 to 8.0 days and cost from $37,047 to $21,856. Similarly, between 1992 and 1997 for MVR, length of stay decreased from 15.6 to 8.1 days and cost from $45,072 to $21,747. The net result over the time period from 1988 to 1997 was an average decline in the cost of operation of $785 a year, adjusted for other factors. Conclusions. This study reveals that outcome of valvular replacement during the period from 1988 to 1997 has remained constant despite the patients becoming older and sicker during the same period. This constant outcome has been accomplished, but length of stay has decreased significantly. Hospital costs increased during the first years of the study period, but then decreased to levels in 1997 that were equal to or significantly less than 1988 levels.

INR reporting in Canadian medical laboratories: an update. Thrombosis Interest Group of Canada.

A written survey of all licensed medical laboratories performing coagulation testing in Canada was undertaken in 1996 as a follow-up to a study performed in 1992. The an overall response rate was 77.4% of the laboratories surveyed. During the 4-year period between surveys, the percentage of responding laboratories using some format for international normalized ratio (INR) reporting increased from 57% to 98%. The mean International Sensitivity Index (ISI) of the various thromboplastins used had decreased from 2.07 to 1.63. However, only 35% of responding laboratories used a thromboplastin with an ISI of 1.2 or less as recommended by the American College of Chest Physicians. In 92% of cases, the ISI was said to be specified for the type of instrument, ie, optical density vs mechanical. However, in only 52% of cases was the ISI known to be specific for the particular reagent-analyzer combination used in the individual laboratory. Nine percent of the laboratories were still using an inappropriate denominator for the INR calculation. While 87% of laboratories quoted a therapeutic INR range of 2.0 to 3.0 for venous thromboembolism, there was much greater variation in the range reported for patients undergoing heart valve replacement. The situation in Canada has improved in using the INR system for prothrombin time reporting. However, additional education is required, as is greater use of thromboplastins with a lower ISI.

Comparison of anesthetic techniques in patients undergoing heart valve replacement

A prospective study of 324 adult patients undergoing operations requiring cardiopulmonary bypass for heart valve replacement was undertaken to determine the effect of anesthetic technique on outcome. Patients received one of three primary techniques: fentanyl (40–100 μg/kg), sufentanil (4–8 μg/kg), or diazepam (0.4–1 mg/kg) with ketamine (3–6 mg/kg). Supplemental inhalation anesthesia with enflurane, halothane, or isoflurane was used in 43.8% of cases. Patients in these anesthetic groupings had similar perioperative demographic and risk classifications. Although there were differences in the requirements for vasopressors postoperatively among the intravenous anesthetic agents, neither mortality rates, length of ICU stay, nor incidence of postoperative heart failure showed the advantage of any intravenous or inhalational agent. There were also no significant differences in the incidences of serious pulmonary, renal, or neurologic morbidity among primary anesthetic techniques nor among supplemental inhalation agents. Multivariate discriminant analysis of these data suggests that many factors are significantly more important than anesthetic technique as determinants of outcome after heart valve replacement.

Carpentier-Edwards Bioprosthesis: A 7-Year Follow-up in 361 Patients

Three hundred sixty-one patients undergoing heart valve replacement with Carpentier-Edwards bioprostheses (CE) were evaluated: 169 patients underwent replacement of the mitral valve (MVR), 124 of the aortic valve (AVR), one of the tricuspid valve (TVR) and 67 of 2 or more valves (mVR). A total of 420 CEs were implanted. Overall operative mortality was 4.7% (7.1 for MVR, 1.6 for AVR, 4.5 for mVR). Early complications included hemorrhage (5 cases), thromboembolism (one case), paraprosthetic leak (one case). Actuarial survival rates at 5 years were computed for overall deaths, cardiac deaths and prosthetic deaths. In the 3 subgroups these 3 rates were respectively 78.7 +/- 5.6%, 82.9 +/- 5.4%, 96.4 +/- 1.6% for MVR, 88.9 +/- 3.3%, 94.2 +/- 2.3%, 98.7 +/- 1.3% for AVR, and 82.3 +/- 5.9%, 88.3 +/- 5.1%, 98.5 +/- 1.5% for mVR. Actuarial freedom from prosthetic complications at 7 years was 59.6 +/- 7.5%, 78.1 +/- 4.1% and 61.9 +/- 8.0% for MVR, AVR and mVR patients. Thromboembolism-free rates were 87.2 +/- 3.9% and 99.2 +/- 0.8% for MVR and AVR, while the thromboembolic linearized rate was 2.8% per patient-year and instantaneous risk of thromboembolism was 4.1% at one and instantaneous risk of thromboembolism was 4.1% at one year for MVR. Anticoagulant-related hemorrhage linearized occurrence was 1.0%, 1.2% and 0.8% per patient-year among the 3 subgroups. Prosthetic endocarditis occurred in 12 patients with a linearized rate of 1.1% per patient-year. Eleven of these patients were treated successfully. Three episodes of primary tissue failure were recorded (0.2% linearized rate per year, instantaneous risk 3.5% at the sixth year).(ABSTRACT TRUNCATED AT 250 WORDS)

Early Clinical Results with the Xenomedica Porcine Bioprosthesis

All patients undergoing heart valve replacement with a glutaraldehyde-preserved Xenomedica xenograft from June 1983 through November 1983, were reviewed. This analysis included 75 patients: 37 having undergone aortic valve replacement, 23 mitral valve replacement, and 15 mitral and aortic valve replacement. Of 70 patients discharged from the hospital, there were 5 late deaths, which represents an incidence of 1.06% per patient-year. Twenty-six patients were recatheterized between 3 and 6 months postoperatively. The mean mitral valve orifice area was 1.57 +/- 0.37 cm2. The average mitral valve gradient was 9.8 +/- 2.9 mmHg. No differences in hemodynamic behavior were found between standard and composite mitral prostheses. The average aortic valve peak systolic gradient was 11 +/- 6 mmHg. Fourteen out of the 34 mitral (41%) and 5 out of 52 aortic (9.6%) prostheses have some degree of incompetence. We have discontinued the use of this cardiac bioprosthesis due to the frequent appearance of incompetence in mitral valves, and high transvalvular gradients in mitral prostheses.

Results and complications with the Omniscience prosthesis

A clinical trial with the Omniscience heart valve was conducted from June, 1980, until May, 1981. In this period 166 patients underwent heart valve replacement: mitral valve replacement (MVR) 70 patients, aortic valve replacement (AVR) 37, and combined mitral-aortic valve replacement (M/AVR) 59 patients. There were 20 hospital deaths, for a mortality of 12%. Total follow-up was 226 patient-years (range 6 to 28 months, mean 18 months). There were eight late deaths (MVR 4.6%, AVR 3.1%, and M/AVR 8.1%). All patients were taking oral anticoagulants. The incidence of valve-related complications (expressed as events per 100 patient-years) was as follows: Systemic embolism--MVR 2, AVR 4.7, and M/AVR 2.5; and anticoagulant complications--MVR 1.9, AVR 2.3, and M/AVR 0. The incidence of valvular dysfunction (expressed as events per 100 patient-years) was as follows: valvular thrombosis--MVR 4.8, AVR 0, and M/AVR 1.2; perivalvular leakage--MVR 1.9, AVR 2.3, and M/AVR 2.5; and infective endocarditis--MVR 0.96, AVR 0, and M/AVR 1.2. The actuarial probability of being free of valvular dysfunction 30 months postoperatively is 73% for the MVR group, 90% for the AVR group, and 71% for the M/AVR group. Despite a short follow-up, the incidence of valvular dysfunction has been significant. For this reason, we have discontinued using these prostheses for heart valve replacement.

Early surgical results of the Medtronic-Hall valve.

A clinical trial with the Medtronic-Hall (M-H) valve was started in November 1981. From then until December 1982, 157 patients underwent heart valve replacement: Mitral valve replacement (MVR) 63 patients, isolated aortic valve replacement (MVR) 41 patients, and 53 underwent combined mitral-aortic valve replacement (MVR + AVR). Hospital mortality was 2.5% overall (4/157). The total follow-up was 147 patient-years (range 1 to 12 months). Late mortality was 3.2% for MVR, 2.5% for AVR and 1.9% for double MVR + AVR. Oral anticoagulation therapy (Dicumarol) was administered to all patients included in this study. There were no anticoagulant complications and no prosthetic bacterial endocarditis registered in this series of patients up to date. The incidence of systemic embolism was 2.5 events per 100 patient-years in the AVR group. No embolic episodes have been registered in the other 2 groups. The incidence of valvular dysfunction (expressed as events per 100 patient-years) were: --Perivalvular leak (0 MVR, 0 AVR and 2 MVR + AVR) --Valve thrombosis (1.7 MVR, 0 AVR and 0 MVR + AVR) --Mechanical dysfunction (1.7 MVR, 0 AVR and 0 MVR + AVR) Despite a short follow-up, the results with the Medtronic-Hall valve are encouraging and compare favorably with other mechanical prostheses.

Comparison of Anesthesia with Diazepam and Ketamine Vs. Morphine in Patients undergoing Heart-Valve Replacement

Because of its analgesic and amnesic effects, ketamine has potential advantages as a primary agent for patients undergoing open-heart surgery. However, the undesirable positive inotropic and chronotropic effects associated with ketamine have deterred its use. Diazepam pretreatment appears to block these unwanted effects. Sixteen randomly selected patients were given a combination of diazepam, 0.4 mg/kg, followed by ketamine, 2 mg/kg, and nitrous oxide, 50 per cent. The authors compared the circulatory responses to induction, intubation, and operation with those obtained in a matched group of patients who received morphine, 3 mg/kg, and nitrous oxide, 50 per cent. All patients underwent mitral- or aortic-valve replacement. Circulatory responses were not significantly different between the two groups. In both groups, heart rate, mean arterial blood pressure, and rate-pressure product increased significantly with intubation of the trachea, incision of the skin, and sternotomy. The incidences of hypertension, hypotension, and arrhythmias, and the need for inotropic drugs were not significantly different between the two groups. No intraoperative awareness occurred in either group. It is concluded that diazepam-ketamine anesthesia is a satisfactory alternative to morphine anesthesia for patients undergoing heartvalve replacement.

Magnesium in patients undergoing open-heart surgery.

Measurements of serum and urinary magnesium levels were made together with the other electrolytes, haematocrit, pH, and albumin in patients comprising two groups—one group of 50 patients undergoing heart valve replacement, and the other, 30 patients undergoing non-perfusion thoracic operations. Low serum magnesium levels were found in some patients admitted to hospital who were or had recently been in congestive heart failure. All patients were found to have low serum magnesium levels postoperatively, but to a greater degree and for a longer period following open-heart surgery. The latter group exhibited hypomagnesuria postoperatively. The literature is reviewed in an attempt to explain the reasons for the changes in the magnesium levels. It is concluded that the changes observed in this limited study warrant further detailed investigation including the use of a double blind trial for assessing the therapeutic value of administering magnesium salts of patients undergoing open-heart surgery.

Bacteriological Profile of Heart Valves Resected from Infective Endocarditis Patients

Background: Early prosthetic valve endocarditis is a serious life threatening infection of newly implanted prosthetic heart valve. A positive post-surgery heart valve culture is a significant risk factor for development of early prosthetic valve endocarditis. Methods: A prospective bacteriological investigation was done in intraoperatively suspected and preoperatively diagnosed infective endocarditis patients undergoing heart valve replacement surgery. The valve samples were cultured after prior homogenization by sterile scalpel method. The bacterial isolates were identified by standard microbiological techniques and their antibiotic susceptibility profile was determined in vitro by Kirby Bauer disc diffusion method. Results: Of 31 heart valve samples cultured, 3 (9.67%) were culture positive which constituted 2 (13.33%) from preoperatively diagnosed infective endocarditis patients from which Staphylococcus aureus and Enterococcus faecalis were isolated and 1 (6.25%) from intraoperatively suspected infective endocarditis patient from which Staphylococcus aureus was isolated. All three isolates were sensitive to antibiotics Vancomycin and Ciprofloxacin and resistant to Penicillin and Amoxycillin. The isolates obtained from preoperatively diagnosed patients were more resistant to antibiotics tested than that from suspected patients. Conclusions: The bacteriological examination of heart valves resected from preoperatively diagnosed and intraoperatively suspected infective endocarditis patients revealed higher degree of culture positivity. Hence routine microbiological examination of all heart valves from diagnosed and suspected IE patients is required to rule out active endocardial infection to reduce the chance of early prosthetic valve endocarditis. Key words: bacteriology; heart valves; infective endocarditis DOI: 10.3126/jnhrc.v7i2.3017 Journal of Nepal Health Research Council Vol.7(2) Apr 2009 108-111