Orathai Pachirat

Analysis of the Impact of Early Surgery on In-Hospital Mortality of Native Valve Endocarditis Use of Propensity Score and Instrumental Variable Methods to Adjust for Treatment-Selection Bias

Background— The impact of early surgery on mortality in patients with native valve endocarditis (NVE) is unresolved. This study sought to evaluate valve surgery compared with medical therapy for NVE and to identify characteristics of patients who are most likely to benefit from early surgery. Methods and Results— Using a prospective, multinational cohort of patients with definite NVE, the effect of early surgery on in-hospital mortality was assessed by propensity-based matching adjustment for survivor bias and by instrumental variable analysis. Patients were stratified by propensity quintile, paravalvular complications, valve perforation, systemic embolization, stroke, Staphylococcus aureus infection, and congestive heart failure. Of the 1552 patients with NVE, 720 (46%) underwent early surgery and 832 (54%) were treated with medical therapy. Compared with medical therapy, early surgery was associated with a significant reduction in mortality in the overall cohort (12.1% [87/720] versus 20.7% [172/832]) and after propensity-based matching and adjustment for survivor bias (absolute risk reduction [ARR] −5.9%, P<0.001). With a combined instrument, the instrumental-variable–adjusted ARR in mortality associated with early surgery was −11.2% (P<0.001). In subgroup analysis, surgery was found to confer a survival benefit compared with medical therapy among patients with a higher propensity for surgery (ARR −10.9% for quintiles 4 and 5, P=0.002) and those with paravalvular complications (ARR −17.3%, P<0.001), systemic embolization (ARR −12.9%, P=0.002), S aureus NVE (ARR −20.1%, P<0.001), and stroke (ARR −13%, P=0.02) but not those with valve perforation or congestive heart failure. Conclusions— Early surgery for NVE is associated with an in-hospital mortality benefit compared with medical therapy alone.

Revisiting the effect of referral bias on the clinical spectrum of infective endocarditis in adults

Referral bias occurs because of the clustering of patients at tertiary care centers. This may result in the distortion of observed clinical manifestations of rare diseases. This analysis evaluates the effect of referral bias on the epidemiology of infective endocarditis (IE) in the International Collaboration on Endocarditis—Prospective Cohort Study (ICE-PCS). This is a prospective multicenter cohort study comparing transferred and non-transferred patients with IE. Factors independently associated with transfer status were evaluated using multivariable logistic regression. A total of 2,760 patients were included in the analysis, of which 1,164 (42.2%) were transferred from other medical centers. Transferred patients more often underwent surgery for IE (odds ratio [OR] = 2.5; 95% confidence interval [CI] 1.9–3.2). They were also more likely to have complications such as stroke (OR = 1.5; 95% CI 1.3–1.9), heart failure (OR = 1.4; 95% CI 1.1–1.6), and new valvular regurgitation (OR = 1.3; 95% CI 1.1–1.6). The in-hospital mortality rates were similar in both groups. Patients with IE who require surgery and suffer complications are referred to tertiary hospitals more frequently than patients with an uncomplicated course. Hospital transfer has no obvious effect on the in-hospital mortality. Referral bias should be taken into consideration when describing the clinical spectrum of IE.

Reduced valve replacement surgery and complication rate in Staphylococcus aureus endocarditis patients receiving acetyl-salicylic acid

OBJECTIVES To assess the influence of acetyl-salicylic acid (ASA) on clinical outcomes in Staphylococcus aureus infective endocarditis (SA-IE). METHODS The International Collaboration on Endocarditis - Prospective Cohort Study database was used in this observational study. Multivariable analysis of the SA-IE cohort compared outcomes in patients with and without ASA use, adjusting for other predictive variables, including: age, diabetes, hemodialysis, cancer, pacemaker, intracardiac defibrillator and methicillin resistance. RESULTS Data were analysed from 670 patients, 132 of whom were taking ASA at the time of SA-IE diagnosis. On multivariable analysis, ASA usage was associated with a significantly decreased overall rate of acute valve replacement surgery (OR 0.58 [95% CI 0.35-0.97]; p<0.04), particularly where valvular regurgitation, congestive heart failure or periannular abscess was the indication for such surgery (OR 0.46 [0.25-0.86]; p<0.02). There was no reduction in the overall rates of clinically apparent embolism with prior ASA usage, and no increase in hemorrhagic strokes in ASA-treated patients. CONCLUSIONS In this multinational prospective observational cohort, recent ASA usage was associated with a reduced occurrence of acute valve replacement surgery in SA-IE patients. Future investigations should focus on ASAs prophylactic and therapeutic use in high-risk and newly diagnosed patients with SA bacteremia and SA-IE, respectively.

Validated Risk Score for Predicting 6‐Month Mortality in Infective Endocarditis

Background Host factors and complications have been associated with higher mortality in infective endocarditis (IE). We sought to develop and validate a model of clinical characteristics to predict 6‐month mortality in IE. Methods and Results Using a large multinational prospective registry of definite IE (International Collaboration on Endocarditis [ICE]–Prospective Cohort Study [PCS], 2000–2006, n=4049), a model to predict 6‐month survival was developed by Cox proportional hazards modeling with inverse probability weighting for surgery treatment and was internally validated by the bootstrapping method. This model was externally validated in an independent prospective registry (ICE‐PLUS, 2008–2012, n=1197). The 6‐month mortality was 971 of 4049 (24.0%) in the ICE‐PCS cohort and 342 of 1197 (28.6%) in the ICE‐PLUS cohort. Surgery during the index hospitalization was performed in 48.1% and 54.0% of the cohorts, respectively. In the derivation model, variables related to host factors (age, dialysis), IE characteristics (prosthetic or nosocomial IE, causative organism, left‐sided valve vegetation), and IE complications (severe heart failure, stroke, paravalvular complication, and persistent bacteremia) were independently associated with 6‐month mortality, and surgery was associated with a lower risk of mortality (Harrells C statistic 0.715). In the validation model, these variables had similar hazard ratios (Harrells C statistic 0.682), with a similar, independent benefit of surgery (hazard ratio 0.74, 95% CI 0.62–0.89). A simplified risk model was developed by weight adjustment of these variables. Conclusions Six‐month mortality after IE is ≈25% and is predicted by host factors, IE characteristics, and IE complications. Surgery during the index hospitalization is associated with lower mortality but is performed less frequently in the highest risk patients. A simplified risk model may be used to identify specific risk subgroups in IE.

Infective Endocarditis in Northeastern Thailand

Despite rigorous diagnostic testing, the cause of infective endocarditis was identified for just 60 (45.5%) of 132 patients admitted to hospitals in Khon Kaen, Thailand, during January 2010–July 2012. Most pathogens identified were Viridans streptococci and zoonotic bacteria species, as found in other resource-limited countries where underlying rheumatic heart disease is common.

One-year outcome following biological or mechanical valve replacement for infective endocarditis.

BACKGROUND Nearly half of patients require cardiac surgery during the acute phase of infective endocarditis (IE). We describe the characteristics of patients according to the type of valve replacement (mechanical or biological), and examine whether the type of prosthesis was associated with in-hospital and 1-year mortality. METHODS AND RESULTS Among 5591 patients included in the International Collaboration on Endocarditis Prospective Cohort Study, 1467 patients with definite IE were operated on during the active phase and had a biological (37%) or mechanical (63%) valve replacement. Patients who received bioprostheses were older (62 vs 54years), more often had a history of cancer (9% vs 6%), and had moderate or severe renal disease (9% vs 4%); proportion of health care-associated IE was higher (26% vs 17%); intracardiac abscesses were more frequent (30% vs 23%). In-hospital and 1-year death rates were higher in the bioprosthesis group, 20.5% vs 14.0% (p=0.0009) and 25.3% vs 16.6% (p<.0001), respectively. In multivariable analysis, mechanical prostheses were less commonly implanted in older patients (odds ratio: 0.64 for every 10years), and in patients with a history of cancer (0.72), but were more commonly implanted in mitral position (1.60). Bioprosthesis was independently associated with 1-year mortality (hazard ratio: 1.298). CONCLUSIONS Patients with IE who receive a biological valve replacement have significant differences in clinical characteristics compared to patients who receive a mechanical prosthesis. Biological valve replacement is independently associated with a higher in-hospital and 1-year mortality, a result which is possibly related to patient characteristics rather than valve dysfunction.

An inspiratory load enhances the antihypertensive effects of home-based training with slow deep breathing: a randomised trial

QUESTION Can adding an inspiratory load enhance the antihypertensive effects of slow breathing training performed at home? DESIGN Randomised trial with concealed allocation. PARTICIPANTS Thirty patients with essential hypertension Stage I or II. INTERVENTION Experimental groups performed slow deep breathing at home, either unloaded or breathing against a load of 20 cmH(2)O using a threshold-loaded breathing device. Participants trained for 30 min, twice daily for 8 weeks. A control group continued with normal activities. OUTCOME MEASURES Resting blood pressure and heart rate were measured at home and in the laboratory before and after the training period. RESULTS Compared to the control group, systolic and diastolic blood pressure decreased significantly with unloaded breathing by means of 13.5 mmHg (95% CI 11.3 to 15.7) and 7.0 mmHg (95% CI 5.5 to 8.5), [corrected] respectively (laboratory measures). With loaded breathing, the reductions were greater at 18.8 mmHg (95% CI 16.1 to 21.5) and 8.6 mmHg (95% CI 6.8 to 10.4), respectively. The improvement in systolic blood pressure was 5.3 mmHg (95% CI 1.0 to 9.6) greater than with loaded compared to unloaded [corrected] breathing. Heart rate declined by 8 beats/min (95% CI 6.5 to 10.3) with unloaded breathing, and 9 beats/min (95% CI 5.6 to 12.2) with loaded breathing. Very similar measures of blood pressure and heart rate were obtained by the patients at home. CONCLUSION Home-based training with a simple device is well tolerated by patients and produces clinically valuable reductions in blood pressure. Adding an inspiratory load of 20 cmH(2)O enhanced the decrease in systolic blood pressure. TRIAL REGISTRATION NCT007919689.

The first reported case of Bartonella endocarditis in Thailand.

Bartonella species have been shown to cause acute, undifferentiated fever in Thailand. A study to identify causes of endocarditis that were blood culture-negative using routine methods led to the first reported case in Thailand of Bartonella endocarditis A 57 year-old male with underlying rheumatic heart disease presented with severe congestive heart failure and suspected infective endocarditis. The patient underwent aortic and mitral valve replacement. Routine hospital blood cultures were negative but B. henselae was identified by serology, PCR, immunohistochemistry and specific culture techniques.

The first reported cases of Q fever endocarditis in Thailand

We describe the first two reported cases of Q fever endocarditis in Thailand. Both patients were male, had pre-existing heart valve damage and had contact with cattle. Heightened awareness of Q fever could improve diagnosis and case management and stimulate efforts to identify risk factors and preventive measures.

Prospective Comparison of Infective Endocarditis in Khon Kaen, Thailand and Rennes, France

Prospectively collected, contemporary data are lacking on how the features of infective endocarditis (IE) vary according to region. We, therefore, compared IE in Rennes, France and Khon Kaen, Thailand. Fifty-eight patients with confirmed IE were enrolled at each site during 2011 and 2012 using a common protocol. Compared with French patients, Thais had a lower median age (47 versus 70 years old; P < 0.001) and reported more animal contact (86% versus 21%; P < 0.001). There were more zoonotic infections among Thai than France patients (6 and 1 cases; P = 0.017) and fewer staphylococcal infections (4 versus 15 cases; P = 0.011). Underlying rheumatic heart disease was more prevalent in Thai than in French patients (31% and 4%; P = 0.001), whereas prosthetic heart valves were less prevalent (9% and 35%; P = 0.001). Our data strengthen previous observations that IE in the tropics has distinctive demographic characteristics, risk factors, and etiologies and underscore the need for improved prevention and control strategies.