Trending Cardiac Biomarkers During Pregnancy in Women With Cardiovascular Disease

BACKGROUND

Clinical utility of cardiac biomarker testing during pregnancy in women with preexisting cardiac disease is not well known. We studied the levels and temporal trends of NT-proBNP (N-terminal pro-B-type natriuretic peptide) and hs-cTnI (high-sensitivity cardiac troponin I) throughout pregnancy in women with preexisting cardiac disease and sought to assess the association between NT-proBNP and hs-cTnI and pregnancy outcomes.

METHODS

Three hundred seven pregnant women with preexisting cardiac disease were prospectively recruited. Mixed-effects linear regression analysis was used to compare the NT-proBNP and hs-cTnI levels between time periods and subgroups. Logistic regression analysis adjusted for maternal age and CARPREG II (Cardiac Disease in Pregnancy) risk score assessed the association between NT-proBNP levels and adverse events.

RESULTS

Geometric mean NT-proBNP (95% CI) was stable through pregnancy with a transient significant increase with labor and delivery (101.4 pg/mL [87.1-118.1], 90.2 pg/mL [78.5-103.6], 153.6 pg/mL [126.8-186.1], and 112.2 pg/mL [94.2-133.7] for first/second trimester, third trimester, labor/delivery and postpartum, respectively). We observed a statistically significant difference in the NT-proBNP between women with preserved versus decreased systemic ventricular function, structurally normal versus abnormal heart, modified World Health Organization class 1, 2 versus modified World Health Organization class 3, 4 and no congenital heart disease versus congenital heart disease. Compared to those without events, median (interquartile range) NT-proBNP levels were significantly higher in those who had heart failure (204 pg/mL [51-450] versus 55 pg/mL [31-97]; P=0.001) and preeclampsia (98 pg/mL [40-319] versus 55 pg/mL [31-99]; P=0.027). NT-proBNP, adjusted for age and CARPREG II risk score, was significantly associated with combined heart failure and preeclampsia (adjusted odds ratio, 2.14 [95% CI, 1.48-3.10] per log NT-proBNP increase; P<0.001). NT-proBNP <200 pg/mL had a specificity of 91% and negative predictive value of 95% in predicting combined heart failure and preeclampsia.

CONCLUSIONS

NT-proBNP remains steady over the course of pregnancy with a transient increase during labor and delivery with higher levels in subgroups of stable cardiac patients. NT-proBNP level of 200 pg/mL can be used in the diagnosis of heart failure/preeclampsia in the pregnant cardiac population.

Psychological Distress in Adults With Congenital Heart Disease Over the COVID-19 Pandemic

Background This study sought to better understand the experiences of adults with congenital heart disease throughout the pandemic. Objectives were to determine (1) psychological distress before and throughout the pandemic; (2) changes in day-to-day functioning; and (3) the percentage of adults with congenital heart disease who experienced COVID-19 related symptoms, underwent testing, and tested positive. Methods and Results This was a cross-sectional study paired with retrospective chart review. A web-based survey was distributed to patients between December 2020 and January 2021. Patients reported on psychological distress across 5 categories (Screening Tool for Psychological Distress; depression, anxiety, stress, anger, and lack of social support), whether they experienced symptoms of COVID-19 and/or sought testing, and changes to their work and social behavior. Five hundred seventy-nine survey responses were received, of which 555 were linked to clinical data. Patients were aged 45±15 years. The proportion of patients reporting above-threshold values for all Screening Tool for Psychological Distress items significantly increased during the early pandemic compared with before the pandemic. Stress returned to baseline in December 2020/January 2021, whereas all others remained elevated. Psychological distress decreased with age, and women reported persistently elevated stress and anxiety compared with men during the pandemic. A consistent trend was not observed with regard to American College of Cardiology/American Heart Association anatomic and physiologic classification. Fifty (9%) patients lost employment because of a COVID-19-related reason. COVID-19 symptoms were reported by 145 (25%) patients, 182 (31%) sought testing, and 10 (2%) tested positive. Conclusions A substantial proportion of adults with congenital heart disease reported clinically significant psychological distress during the pandemic.

Increasing age and atrial arrhythmias are associated with increased thromboembolic events in a young cohort of adults with repaired tetralogy of Fallot

BACKGROUND

Adults with repaired Tetralogy of Fallot (rTOF) comprise one of the largest cohorts among adults with congenital heart disease (ACHD). These patients have a higher burden of atrial arrhythmias (AA), leading to increased adverse events, including stroke and transient ischemic attack (TIA). However, the data on factors associated with stroke/TIA in rTOF are limited, and classic risk factors may not apply. We studied event rates and associated factors for thromboembolism in a rTOF cohort.

METHODS

Retrospective cohort study of all adult patients age >18 years with rTOF followed at a single ACHD tertiary care center. AA of interest were atrial fibrillation (AF) and atrial flutter (AFL).

RESULTS

Data from 260 patients were identified, mean age 37.6 SD 13.3 years, followed over 5108 patient-years (mean 16.6 SD 8.2 years). 43 patients had AF and/or AFL, and 30 patients had thromboembolic events, of which 19 patients had stroke/TIA. The event rate for any thromboembolism was 3.39 per 100 patient-years follow-up in patients with AA, compared to 1.80 in patients without (P = .07). In univariate analysis, older age and diabetes were associated with thromboembolic events. In multivariate analysis, only older age was associated with thromboembolic events.

CONCLUSIONS

In our relatively young cohort of adults with rTOF, there was a high prevalence of AA, associated with nearly double the rate of thromboembolic events compared to patients without AA. Older age alone is independently associated with thromboembolic events. Further studies into assessment of silent AA are required, and routine assessments should be considered at an earlier age.

Pregnancy related changes in Doppler gradients and left ventricular mechanics in women with sub-valvular or valvular aortic stenosis

BACKGROUND

The aim of our study was to characterize echocardiographic changes during pregnancy in women with known LVOT obstruction or AS compared to the healthy pregnancy controls, and to assess the relationship with pregnancy outcomes.

METHODS

We retrospectively studied 34 pregnant patients with congenital LVOT obstruction or AS with healthy age-matched pregnant controls. Patients with other significant valvular lesions, structural heart disease (LVEF < 40%), or prior valve surgery were excluded. All LVOTO/AS patients underwent a minimum of two consecutive echocardiograms between 1 year pre-conception and 1 year postpartum, with at least two studies during the pregnancy. Comprehensive echocardiographic evaluation was performed including speckle-tracking LV global longitudinal strain.

RESULTS

A total of 83 echocardiograms from the study group and 34 echocardiograms from the control group were evaluated. Over the range of LVOTO/AS, a significantly greater increase in the AV gradients and LV and LA volumes were observed as compared with the controls. In the sub-group of LVOTO/AS pregnant women with ≥ moderate (n = 8) versus < moderate LVOTO/AS (n = 26), averaged 2^nd /3^rd trimester LVEF was lower (51 ± 12)% versus (58 ± 4)%, (p = 0.02) and GLS was lower (-19.5 ± 2.8) versus (21.2 ± 2.4), (p = 0.06). Pregnancy was well tolerated despite these changes.

CONCLUSION

Among pregnant women with even milder forms of LVOTO/AS, increases in cardiac volumes and AV gradients can be expected over the course of pregnancy. Significant decreases in LV function and mechanics were only observed in women with moderate or greater LVOTO/AS, although still remained in normal range.

Impact of COVID-19 Pandemic on Cardiovascular Testing in Asia

Background

The coronavirus disease-2019 (COVID-19) pandemic significantly affected management of cardiovascular disease around the world. The effect of the pandemic on volume of cardiovascular diagnostic procedures is not known.

Objectives

This study sought to evaluate the effects of the early phase of the COVID-19 pandemic on cardiovascular diagnostic procedures and safety practices in Asia.

Methods

The International Atomic Energy Agency conducted a worldwide survey to assess changes in cardiovascular procedure volume and safety practices caused by COVID-19. Testing volumes were reported for March 2020 and April 2020 and were compared to those from March 2019. Data from 180 centers across 33 Asian countries were grouped into 4 subregions for comparison.

Results

Procedure volumes decreased by 47% from March 2019 to March 2020, showing recovery from March 2020 to April 2020 in Eastern Asia, particularly in China. The majority of centers cancelled outpatient activities and increased time per study. Practice changes included implementing physical distancing and restricting visitors. Although COVID testing was not commonly performed, it was conducted in one-third of facilities in Eastern Asia. The most severe reductions in procedure volumes were observed in lower-income countries, where volumes decreased 81% from March 2019 to April 2020.

Conclusions

The COVID-19 pandemic in Asia caused significant reductions in cardiovascular diagnostic procedures, particularly in low-income countries. Further studies on effects of COVID-19 on cardiovascular outcomes and changes in care delivery are warranted.

Risk Associated With Valvular Regurgitation During Pregnancy

BACKGROUND

Pregnancies in women with regurgitant valve lesions are generally considered low risk, but this has not been well studied.

OBJECTIVES

This study determined the frequency of adverse cardiac events (CEs) in pregnant women with moderate or severe regurgitant valve lesions.

METHODS

Maternal and fetal outcomes in women with moderate or severe chronic valve regurgitation enrolled in a prospective multicenter study on pregnancy outcomes were examined. Adverse CEs included heart failure, sustained arrhythmias, cardiac arrest, or death. A multivariate logistic regression model was used to identify determinants of CEs in women at the highest risk.

RESULTS

Outcomes of 430 pregnancies in women with moderate or severe regurgitant lesions were examined: 145 with mitral regurgitation (MR), 101 with pulmonary regurgitation (PR), 71 with multivalve disease, 73 with tricuspid regurgitation (TR), and 40 with aortic regurgitation (AR). Most women had associated congenital or acquired heart disease. Adverse CEs occurred in 13% of pregnancies: 27% of pregnancies with multivalve disease; 15% with MR; 15% with TR; 5% with AR; and 3% with PR. Maternal mortality was rare. In women with MR, TR, or multivalve disease (n = 289), left ventricular systolic dysfunction (p = 0.001), pulmonary hypertension (p = 0.005), and cardiac events before pregnancy (p < 0.001) were important determinants of CEs during pregnancy.

CONCLUSIONS

Women with AR and PR are at low risk for cardiac complications during pregnancy. While many women with MR, TR, and multivalve regurgitation do well during pregnancy, additional clinical variables help stratify those at highest risk. This new information will enhance the quality and precision of preconception counseling and pregnancy planning.

Cardiac Risk Score to Predict Small-for-Gestational-Age Infants in Pregnant Women with Heart Disease

BACKGROUND

One of the most common fetal complications in pregnant women with cardiovascular disease is small for gestational age (SGA) which is associated with a higher risk of perinatal morbidity/mortality and poor long-term health outcomes. The objective of this study was to identify cardiac determinants/derive a risk score of clinically relevant SGA < 5^th percentile (SGA-5^th).

METHODS

A prospective cohort of 1812 pregnancies in women with heart disease was studied. SGA-5^th was the outcome of interest, defined as birth weight less than 5^th percentile for gestational age and sex. Multivariable logistic regression analysis identified predictors for SGA-5^th. Based on the regression coefficients a weighted risk score was created.

RESULTS

SGA-5^th complicated 10% of pregnancies, eleven predictors of SGA-5^th were identified and each was assigned a weighted score: maternal cyanosis (8), Fontan palliation (7), smoking (3), moderate or severe valvular regurgitation (3), beta-blocker use throughout pregnancy (4) or only in the 2^nd and 3^rd trimester (2), high baseline beta-blocker dose (4), BMI < 18.5 (3) or 18.5-24.9 (1), Asian/other ethnicity (2) and significant outflow tract obstruction (1). In the absence of identified risk factors, the risk of SGA-5^th was approximately 4%. Pregnancies with risk scores/SGA-5^th rate were as follows: 0/4%, 1/5%, 2/7%, 3/9%, 4/12%, 5/14%, 6/18%, 7/23%, 8/28% and ≥ 9/34%.

CONCLUSIONS

There are a number of cardiac predictors that are associated with increased risk of SGA-5^th. This is a prognostically important outcome and consideration should be given to routinely predicting and modifying the risk whenever possible.

Aortic Dimensions, Biophysical Properties, and Plasma Biomarkers in Children and Adults with Marfan or Loeys-Dietz Syndrome

Background

Aortic dilation, stiffening, and dissection are common and potentially lethal complications of Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS), which involve abnormal transforming growth factor beta (TGF-β) signalling. The relation of aortic dimensions, stiffness, and biomarker levels is unknown. The objective of this study was to measure aortic dimensions, stiffness, TGF-β and matrix metalloproteinase (MMP) levels, and endothelial function in patients with MFS, and to compare TGF-β levels in patients with MFS receiving different therapeutic regimens.

Methods

This was a cohort study of 40 MFS and 4 LDS patients and 87 control participants. Aortic dimension and stiffness indexes, including pulse wave velocity (PWV), were measured using echocardiography and Doppler. Total and free TGF-β and MMP blood levels were measured using Quantikine (R&D Systems, Inc, Minneapolis, MN) and Quanterix (Billerica, MA) kits. Endothelial function was measured using brachial artery flow-mediated dilation.

Results

PWV was increased in patients with MFS. There were increased MMP-2 levels in those with MFS but no increase in free or total TGF-β or MMP-9 levels compared with control participants. There was no difference in TGF-β levels between MFS patients receiving no medications, angiotensin receptor blockers, and β-blockers. PWV correlated most strongly with age. Endothelial function showed premature gradual decline in patients with MFS.

Conclusions

Despite the increased PWV, monitoring aortic stiffness or TGF-β levels would not be helpful in patients with MFS. TGF-β levels were not increased and the increased MMP-2 levels suggest consideration of a different therapeutic target.

Preventing Complications in Pregnant Women With Cardiac Disease

BACKGROUND

Pregnancy can lead to complications in women with heart disease, and these complications can be life threatening. Understanding serious complications and how they can be prevented is important.

OBJECTIVES

The primary objectives were to determine the incidence of serious cardiac events (SCEs) in pregnant women with heart disease, whether they were preventable, and their impact on fetal and neonatal outcomes. Serious obstetric events were also examined.

METHODS

A prospectively assembled cohort of 1,315 pregnancies in women with heart disease was studied. SCEs included cardiac death or arrest, ventricular arrhythmias, congestive heart failure or arrhythmias requiring admission to an intensive care unit, myocardial infarction, stroke, aortic dissection, valve thrombosis, endocarditis, and urgent cardiac intervention. The Harvard Medical Study criteria were used to adjudicate preventability.

RESULTS

Overall, 3.6% of pregnancies (47 of 1,315) were complicated by SCEs. The most frequent SCEs were cardiac death or arrest, heart failure, arrhythmias, and urgent interventions. Most SCEs (66%) occurred in the antepartum period. Almost one-half of SCEs (49%) were preventable; the majority of preventable SCEs (74%) were secondary to provider management factors. Adverse fetal and neonatal events were more common in pregnancies with SCEs compared with those without cardiac events (62% vs. 29%; p < 0.001). Serious obstetric events were less common (1.7%) and were primarily due to pre-eclampsia with severe features.

CONCLUSIONS

Pregnant women with heart disease are at risk for serious cardiac complications, and approximately one-half of all SCEs are preventable. Strategies to prevent serious cardiac complications in this high-risk cohort of women need to be developed.

Atrial arrhythmias and thromboembolic complications in adults post Fontan surgery

Objective

Patients with Fontan surgery experience late complications in adulthood. We studied the factors associated with the development and maintenance of atrial arrhythmias and thromboembolic complications in an adult population with univentricuar physiology post Fontan surgery.

Methods

Single centre retrospective cohort study of patients ≥18 years of age with Fontan circulation followed at our quaternary care centre for more than 1 year were included. Univariate and multivariate regression models were used where applicable to ascertain clinically significant associations between risk factors and complications.

Results

93 patients were included (age 30.2±8.8 years, 58% men). 28 (30%) had atriopulmonary Fontan connection, 35 (37.6%) had lateral tunnel Fontan and 29 (31.1%) had extracardiac Fontan pathway. After a mean of 7.27±5.1 years, atrial arrhythmia was noted in 37 patients (39.8%), of which 13 developed had atrial fibrillation (14%). The presence of atrial arrhythmia was associated with the number of prior cardiac surgeries/procedures, increasing age and prior atriopulmonary Fontan operation. Thromboembolic events were present in 31 patients (33%); among them 14 had stroke (45%), 3 had transient ischaemic attack (9.7%), 7 had pulmonary embolism (22.6%) and 5 had atrial thrombus with imaging (16.1%). The presence of thromboembolic events was only associated with age and the presence of cirrhosis in multivariate analysis.

Conclusions

Atrial arrhythmias are common in adults with Fontan circulation at an early age, and are associated with prior surgical history and increasing age. Traditional risk factors may not be associated with atrial arrhythmia or thromboembolism in this cohort.

A Postpartum Type A Dissection

A 28-year-old woman with familial thoracic aortic aneurysm and dissection syndrome and a mildly dilated aorta presented 3 days postpartum with a type A aortic dissection. This case illustrates the unpredictability of this disease and the challenges with risk stratification of women with underlying aortopathy contemplating pregnancy. (Level of Difficulty: Intermediate.)

Impact of frequent premature ventricular contractions on pregnancy outcomes

OBJECTIVES

To determine cardiac and fetal/neonatal event rates among pregnant women with premature ventricular contractions (PVCs) and compare with control groups.

METHODS

Prospective case-control cohort study: 53 consecutive pregnancies in 49 women referred to the St. Paul's Hospital between 2010 and 2016 with PVC burden >1% in women without underlying cardiac disease. Maternal cardiac and fetal/neonatal outcomes were compared with two pregnant control groups: (1) supraventricular tachycardia (SVT) group of 53 women referred for a history of SVT/SVT in the current pregnancy and (2) low-risk group of 53 women with no cardiac disease.

RESULTS

The maximal PVC burden was 9.2% (range 1.1%-58.7%). Six of 53 (11%) pregnancies were complicated by a maternal cardiac event: heart failure n=1 and sustained ventricular tachycardia requiring therapy n=5 as compared with no cardiac events in both control groups. All women with an adverse event had a PVC burden >5%. Seven (13%) pregnancies were complicated by an adverse fetal and/or neonatal event and this was similar to the normal control group (5 (9%), P=0.45) and significantly less than the SVT group (16 (30%), P=0.03). The adverse fetal event was driven by small for gestational age neonates and preterm delivery.

CONCLUSIONS

In our cohort of pregnant women with a structurally normal heart and 'high' PVC burden, we found an adverse maternal event rate of 11%, and all events were successfully managed with medical therapy. The rate of adverse fetal events in the PVC group was similar to the normal control group.

Right ventricle to pulmonary artery conduit reoperations in patients with tetralogy of fallot or pulmonary atresia associated with ventricular septal defect

The short lifespan of right ventricle-to-pulmonary artery (RV-PA) conduits used in repairs of complex congenital heart defects makes future surgical replacement inevitable. Percutaneous pulmonary valve implantation (PPVI) now offers an attractive alternative to surgery in some patients. The objectives of this study were to examine the pattern of conduit reoperations, the factors affecting conduit longevity, and to discuss the role of PPVI in these patients. Forty-nine patients (mean age 27 ± 8 years) with pulmonary atresia or pulmonary stenosis with tetralogy of Fallot who underwent surgery for RV-PA conduits from September 1974 to October 2011 were reviewed. A total of 106 RV-PA conduits were implanted, 57 of which were replacements. Second, third, and fourth conduits were required during the follow-up period in 39, 16, and 2 patients, respectively. Freedom from reoperation at 10 years for the first, second, and third conduits was 50%, 74%, and 86%, respectively. Significant independent predictors of shorter conduit longevity included smaller conduit and conduit type (homograft and other vs Dacron). Furthermore, a significant proportion (32 of 57 [56%]) of conduit replacements took place from ages 9 to 18 years. There were 37 adults whose current existing conduits had not yet failed, with 73% (27 of 37) potentially suitable in the future for PPVI on the basis of conduit size of 16 to 27 mm. In conclusion, multiple RV-PA conduit revisions were required in patients who survived to adulthood, with many replacements taking place during adolescence. Most conduits in this adult cohort met size criteria for PPVI, thereby offering these patients a potential alternative to surgical intervention for conduit failure.

A case of Starr-Edwards valve thrombosis in pregnancy

Starr-Edwards ball-in-cage prosthetic heart valves, although durable, are associated with a particularly high rate of thromboembolic complications. This valve is seldom used in North America, and is certainly not the valve of choice in a woman of childbearing age. Few reports exist from the 1970s of thrombotic complications in pregnant women with Starr-Edwards prostheses, and the optimal management strategy for such valves is unclear. Here, the case is reported of a 31-year-old woman with a Starr-Edwards prosthesis in the mitral position who was transferred to the authors' center at six weeks' gestation with pulmonary edema. Transthoracic echocardiography demonstrated thrombosis of the prosthetic valve, with a mean gradient of 23 mmHg. When treated initially with intravenous heparin and furosemide the patient improved significantly; however, the optimal management going forward was unclear. Here, the options for anticoagulation during pregnancy and for management in the event of valve thrombosis are reviewed. In the absence of any clear guidelines, a thorough discussion of the various risks and benefits with the patient is necessary, but ultimately any consideration of the risk to the mother is paramount.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: executive summary

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. They have distinctive forms of heart failure, and their cardiac disease can be associated with pulmonary hypertension, thromboemboli, complex arrhythmias and sudden death.Medical aspects that need to be considered relate to the long-term and multisystemic effects of single-ventricle physiology, cyanosis, systemic right ventricles, complex intracardiac baffles and failing subpulmonary right ventricles. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the understanding of the late outcomes, genetics, medical therapy and interventional approaches in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. The present executive summary is a brief overview of the new guidelines and includes the recommendations for interventions. The complete document consists of four manuscripts that are published online in the present issue of The Canadian Journal of Cardiology, including sections on genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy and contraception risks, and follow-up requirements. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

Canadian Cardiovascular Society 2009 Consensus Conference on the management of adults with congenital heart disease: outflow tract obstruction, coarctation of the aorta, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome

With advances in pediatric cardiology and cardiac surgery, the population of adults with congenital heart disease (CHD) has increased. In the current era, there are more adults with CHD than children. This population has many unique issues and needs. Since the 2001 Canadian Cardiovascular Society Consensus Conference report on the management of adults with CHD, there have been significant advances in the field of adult CHD. Therefore, new clinical guidelines have been written by Canadian adult CHD physicians in collaboration with an international panel of experts in the field. Part II of the guidelines includes recommendations for the care of patients with left ventricular outflow tract obstruction and bicuspid aortic valve disease, coarctation of the aorta, right ventricular outflow tract obstruction, tetralogy of Fallot, Ebstein anomaly and Marfan's syndrome. Topics addressed include genetics, clinical outcomes, recommended diagnostic workup, surgical and interventional options, treatment of arrhythmias, assessment of pregnancy risk and follow-up requirements. The complete document consists of four manuscripts that are published online in the present issue of The Canadian Journal of Cardiology. The complete document and references can also be found at www.ccs.ca or www.cachnet.org.

Transcatheter pulmonary valve implantation using the Edwards SAPIEN transcatheter heart valve

BACKGROUND

Conduits placed in the right ventricular outflow tract (RVOT) have limited longevity which often requires increasingly complex reoperations. Transcatheter pulmonary valve implantation improves conduit hemodynamics through a minimally invasive approach. We present data for 7 patients treated with the Edwards SAPIEN transcatheter heart valve (THV).

PATIENTS

Patients' ranged in age from 16 to 52 years, one was female, and all had NYHA class II-III symptoms. Patients had pulmonary homografts that had been placed 2-25 years earlier during the Ross procedure (n = 4), repaired double outlet right ventricle with situs inversus (n = 1), or Rastelli repair for D-TGA, pulmonary atresia, and ventricular septal defect (n = 2). Patients had either severe pulmonary stenosis and/or moderate to severe pulmonary regurgitation.

RESULTS

All patients had successful percutaneous implantation of the 23 mm SAPIEN THV under general anesthesia. Fluoroscopy times ranged from 16 to 49 mins and procedure times ranged from 110 to 237 mins. The RV:systemic pressure ratio decreased from 78 +/- 18 to 39 +/- 8%, the RVOT gradient improved from 60.7 +/- 24.3 to 14.9 +/- 6.9 mm Hg, no patients had pulmonary insufficiency, and all patients had symptom improvement. At a maximum follow-up of 3.5 years (median 22.5 months), Doppler peak gradients ranged from 7-36 mm Hg, and there is no evidence of late stent fracture or structural valve failure.

CONCLUSION

The SAPIEN THV can be used successfully in the treatment of patients with right ventricle to pulmonary artery homograft failure. The valve is durable to at least 3.5 years without stent fracture or regurgitation. Clinical trials are underway to assess the long-term safety and efficacy of this valve.

CCS/CAR/CANM/CNCS/CanSCMR joint position statement on advanced noninvasive cardiac imaging using positron emission tomography, magnetic resonance imaging and multidetector computed tomographic angiography in the diagnosis and evaluation of ischemic heart disease--executive summary

BACKGROUND

Over the past few decades, advanced imaging modalities with excellent diagnostic capabilities have emerged. The aim of the present position statement was to systematically review existing literature to define Canadian recommendations for their clinical use.

METHODS

A systematic literature review to 2005 was conducted for positron emission tomography (PET), multidetector computed tomographic angiography and magnetic resonance imaging (MRI) in ischemic heart disease. Papers that met the criteria were reviewed for accuracy, prognosis data and study quality. Recommendations were presented to primary and secondary panels of experts, and consensus was achieved.

RESULTS

Indications for PET include detection of coronary artery disease (CAD) with perfusion imaging, and defining viability using fluorodeoxyglucose to determine left ventricular function recovery and/or prognosis after revascularization (class I). Detection of CAD in patients, vessel segments and grafts using computed tomographic angiography was considered class IIa at the time of the literature review. Dobutamine MRI is class I for CAD detection and, along with late gadolinium enhancement MRI, class I for viability detection to predict left ventricular function recovery. Imaging must be performed at institutions and interpreted by physicians with adequate experience and training.

CONCLUSIONS

Cardiac imaging using advanced modalities (PET, multidetector computed tomographic angiography and MRI) is useful for CAD detection, viability definition and, in some cases, prognosis. These modalities complement the more widespread single photon emission computed tomography and echocardiography. Given the rapid evolution of technology, initial guidelines for clinical use will require regular updates. Evaluation of their integration in clinical practice should be ongoing; optimal use will require proper training. A joint effort among specialties is recommended to achieve these goals.

The Extensive Lifestyle Management Intervention (ELMI) after cardiac rehabilitation: a 4-year randomized controlled trial

BACKGROUND

Previous reports indicate risk factors and lifestyle behaviors may deteriorate early after completion of a cardiac rehabilitation program (CRP). We hypothesized that a modest risk factor and lifestyle management intervention after a CRP would significantly reduce overall cardiovascular risk using the Framingham risk score compared with usual care after 4 years.

METHODS

Patients with ischemic heart disease (n = 302) were randomized after a CRP to either usual care or intervention (exercise sessions, telephone follow-ups, counseling sessions, and reports to the participants' family physicians). The Framingham risk score, risk factors, and lifestyle behaviors were compared after 4 years.

RESULTS

Data were available for 130 intervention and 119 usual care participants. The intervention resulted in 15.5 hours of direct participant contact. Framingham score, total cholesterol, low-density lipoprotein cholesterol, and systolic blood pressure were significantly improved in the intervention group after adjusting for baseline factors. There were no significant differences with respect to lifestyle factors between the groups.

CONCLUSIONS

A modest risk factor and lifestyle management intervention resulted in a significant reduction to global risk compared with usual care and should be considered after CRP.

Treating the right patient at the right time: access to cardiovascular nuclear imaging

Cardiovascular nuclear medicine uses agents labelled with radioisotopes that can be imaged with cameras (single-photon emission tomography [SPECT] or positron emission tomography [PET]) capable of detecting gamma photons to show physiological parameters such as myocardial perfusion, myocardial viability or ventricular function. There is a growing body of literature providing guidelines for the appropriate use of these techniques, but there are little data regarding the appropriate timeframe during which the procedures should be accessed. An expert working group composed of cardiologists and nuclear medicine specialists conducted an Internet search to identify current wait times and recommendations for wait times for a number of cardiac diagnostic tools and procedures, including cardiac catheterization and angioplasty, bypass grafting and vascular surgery. These data were used to estimate appropriate wait times for cardiovascular nuclear medicine procedures. The estimated times were compared with current wait times in each province. Wait time benchmarks were developed for the following: myocardial perfusion with either exercise or pharmacological stress and SPECT or PET imaging; myocardial viability assessment with either fluorodeoxyglucose SPECT or PET imaging, or thallium-201 SPECT imaging; and radionuclide angiography. Emergent, urgent and nonurgent indications were defined for each clinical examination. In each case, appropriate wait time benchmarks were defined as within 24 h for emergent indications, within three days for urgent indications and within 14 days for nonurgent indications. Substantial variability was noted from province to province with respect to access for these procedures. For myocardial perfusion imaging, mean emergent/urgent wait times varied from four to 24 days, and mean nonurgent wait times varied from 15 to 158 days. Only Ontario provided limited access to viability assessment, with fluorodeoxyglucose available in one centre. Mean emergent/urgent wait times for access to viability assessment with thallium-201 SPECT imaging varied from three to eight days, with the exception of Newfoundland, where an emergent/urgent assessment was not available; mean nonurgent wait times varied from seven to 85 days. Finally, for radionuclide angiography, mean emergent/urgent wait times varied from two to 20 days, and nonurgent wait times varied from eight to 36 days. Again, Newfoundland centres were unable to provide emergent/urgent access. The publication of these data and proposed wait times as national targets is a step toward the validation of these recommendations through consultation with clinicians caring for cardiac patients across Canada.

The Extensive Lifestyle Management Intervention (ELMI) following cardiac rehabilitation trial

AIM

Previous studies have reported lifestyle and risk factor deterioration following completion of a cardiac rehabilitation program (CRP). We report the results of a one-year Extensive Lifestyle Management Intervention (ELMI) aimed at preventing these adverse changes.

METHODS AND RESULTS

A total of 302 men and women with ischaemic heart disease were recruited following completion of a CRP and randomized to either the ELMI (consisting of exercise sessions, telephone follow-ups and risk factor and lifestyle counselling) or usual care. The primary outcome was global cardiovascular risk using the Framingham and Procam risk scores. Secondary outcomes included risk factors and lifestyle behaviours. Baseline characteristics were similar between the two groups. Adherence to the ELMI was high. There was a non-significant trend in favour of the ELMI between for both the Framingham (6.6+/-3.1 to 6.2+/-2.9 vs 6.6+/-3.2 to 6.7+/-3.2, P=0.138) and Procam (20.0+/-20.0 to 20.6+/-19.5 vs 19.1+/-18.7 to 21.8+/-19.1, P=0.089) scores. There were no differences in secondary outcomes.

CONCLUSIONS

A one-year multi-factorial post-CRP intervention results in modest, non-significant benefits to global risk compared to usual care. The absence of deterioration in the usual care group may be due to improved practices in usual care.

A mycorrhiza-responsive protein in wheat roots

A small protein, designated Myk15, was found to be strongly induced in wheat ( Triticum aestivum) roots colonized by the arbuscular mycorrhizal fungus Glomus intraradices. This protein, which is most abundant in root fractions characterized by strong mycorrhizal colonization, has been characterized using two-dimensional polyacrylamide gel electrophoresis and microsequencing. It has an apparent molecular mass of 15 kDa and an isoelectric point of 4.5. The N-terminal sequence has high similarity to a peptide sequence deduced from an expressed sequence tag (EST) clone derived from Medicago truncatula roots colonized by G. intraradices. This EST clone is predicted to code for a protein with a similar size and isoelectric point as Myk15. The N-terminus of the deduced M. truncatula protein contains a highly hydrophobic stretch of 24 amino acid residues preceding the region with high similarity to the Myk15 N-terminus. This hydrophobic stretch is predicted to form a transmembrane alpha-helix and may correspond to a cleavable targeting domain.

A randomized controlled trial of an extensive lifestyle management intervention (ELMI) following cardiac rehabilitation: study design and baseline data

BACKGROUND

Cardiac rehabilitation programs (CRP) represent comprehensive interventions that are typically limited to four months. Following completion of CRP, it appears that risk factors and lifestyle behaviours may deteriorate. The Extensive Lifestyle Management Intervention (ELMI) Following Cardiac Rehabilitation trial will investigate the benefits of a randomized intervention to prevent these adverse changes.

METHODS

Patients with ischemic heart disease (IHD) were randomized following a standard CRP to the ELMI or to usual care. The ELMI program is a case-managed intervention aimed at individualizing risk factor and lifestyle management based on current treatment guidelines. The program consists of cardiac rehabilitation sessions, telephone follow-up and risk factor and lifestyle counselling sessions. Health professionals work with participants using behavioural counselling and communications with participants' family physicians. Usual care participants return to their family physicians' care, and come to the study clinic only to undergo annual outcomes assessment. The primary outcome is change in IHD global risk after four years. Secondary outcomes include combined cardiovascular events, health care utilization, lifestyle adherence, quality of life and risk factors.

RESULTS

Over 28 months, 302 men and women were randomized. This represented 29% of the total population screened. The average age of study participants is 64 years, 18% are women, 53% have had a previous myocardial infarction, 73% have undergone previous revascularization and 20% have diabetes mellitus. Ischemic heart disease risk factors for the entire cohort improved significantly after subjects had gone through previous CRPs. Baseline risk factors, lifestyle behaviours and medications were similar between the groups.

CONCLUSIONS

This study population is representative of patients completing a standard CRP. Results of the ELMI trial will provide valuable information for the future design of CRPs.

Subcellular distribution of 14-3-3 proteins in the unicellular green alga Chlamydomonas reinhardtii

A polyclonal antibody was raised against a recombinant Chlamydomonas 14-3-3-beta-galactosidase (beta-Gal) fusion protein and characterized for its epitope specificity towards the corresponding Chlamydomonas 14-3-3 protein by scan-peptide analysis. This antibody recognized four Chlamydomonas polypeptides with apparent molecular masses 32, 30, 27, and 24 kDa, which also reacted with the antiserum depleted of anti-(Escherichia coli beta-Gal) IgG, but not with the corresponding preimmune serum or the antiserum preincubated with purified 14-3-3 proteins. Western-blot analyses performed with the antibody depleted of anti-(beta-Gal) IgG revealed that more or less pronounced levels of 14-3-3 proteins were present in all subcellular fractions of Chlamydomonas reinhardtii except the nuclei. The highest levels of 14-3-3 protein were observed in the cytosol and microsomal fraction. The 30-kDa isoform was predominant in the cytosol, whereas the 27-kDa isoform was prevalent in the microsomes. When microsomal membranes were separated by sucrose-density-gradient centrifugation, Western-blot analysis revealed distinct patterns of 14-3-3 isoforms in the endoplasmic reticulum, dictyosome, and plasma membrane fractions identified by marker enzyme activities. These findings indicate that the four 14-3-3 proteins of C. reinhardtii differentially interact with endoplasmic reticulum, dictyosomes, and plasma membrane.

Phase I-II study of escalating doses of amifostine combined with high-dose cyclophosphamide

PURPOSE

To evaluate the feasibility and clinical effects of increasing doses of amifostine administered four times in 1 day with high-dose (HD) cyclophosphamide (CTX).

METHODS

A group of 16 patients with a diagnosis of lymphoma were treated with HD-CTX given at a total dose of 7 g/m2 subdivided into four doses, each preceded by increasing doses of amifostine. A group of 12 lymphoma patients previously treated with the same HD-CTX regimen was used as historical controls.

RESULTS

The dose of amifostine was escalated in cohorts of three patients each from 4x570 mg/m2 to 4x910 mg/m2 without severe toxic effects. Further patients were treated at the highest dose level. Side effects included a fall in blood pressure (always less than 20% of baseline value), asymptomatic hypocalcemia (from a median value of 2.4 to 1.7 mmol/l) and a decrease in creatinine clearance (from a median value of 102 to 85 ml/min). The parameters of hematotoxicity for patients treated in the study were not significantly different from those of the historical control patients.

CONCLUSIONS

Amifostine can be given safely at a dose of 910 mg/m2 four times in 1 day in combination with HD-CTX. With this schedule amifostine did not show a myeloprotective effect.

Method for determining protein kinase substrate specificities by the phosphorylation of peptide libraries on beads, phosphate-specific staining, automated sorting, and sequencing

A method is described for the elucidation of the peptide substrate phosphorylation specificity of a protein kinase. Peptide libraries with two to six degenerate positions and a length of seven or nine amino acids were generated directly on Sepharose beads by solid-phase peptide synthesis according to the split-and-mix procedure. The immobilized peptides were incubated with the catalytic subunit of the cyclic AMP-dependent protein kinase (PKA) as a model enzyme resulting in the phosphorylation of the beads that contain the recognition motif of the kinase. The beads were then stained with a new phosphate-monoester-specific fluorescent dye consisting of a complex of iron(III) with fluorescein-coupled iminodiacetic acid. A flow cytometer was used to analyze the phosphorylation efficiency and the beads with the highest phosphorylation degree were isolated by the use of a fluorescence-activated cell sorter. Pool sequencing of those beads revealed the preferred kinase motif. The results are in good agreement with data from the literature. The method lends itself to the rapid elucidation of the specificity of uncharacterized protein kinases.

Xylose utilisation: cloning and characterisation of the Xylose reductase from Candida tenuis

Xylose reductases catalyse the initial reaction in the xylose utilisation pathway, the NAD(P)H+H+ dependent reduction of xylose to xylitol. In this work, the xylose reductase gene from Candida tenuis CBS 4435 was cloned and successfully expressed in E. coli. From the purified and partially sequenced protein primers were deduced for PCR. The fragment obtained was used for Southern blot analysis and screening of a subgenomic library. The clone containing the open reading frame was sequenced; the gene consisted of 969 nucleotides coding for a 322 amino acids protein with a molecular mass of 36 kDa. Putative regulatory signals were identified with the help of a Saccharomyces cerevisiae regulatory sequence database. In order to express the xylose reductase in E. coli, the gene was placed under positive and negative control. At low temperatures, the xylose reductase was expressed in soluble and active form up to about 10% of the soluble protein; with rising temperatures formation of visible inclusion bodies occurred. In refolding experiments we were able to recover the major portion of xylose reductase activity from the pellet fraction.

Xylose utilisation: cloning and characterisation of the xylitol dehydrogenase from Galactocandida mastotermitis

We cloned and successfully expressed the gene for xylitol dehydrogenase from Galactocandida mastotermitis in Escherichia coli. The amino acid sequence revealed that the enzyme belongs to the superfamily of zinc containing, medium-chain alcohol dehydrogenases. The enzyme catalyses the second step in the xylose utilising pathway converting xylose to xylulosephosphate. Xylulose-phosphate is further degraded by the transaldolase and transketolase reactions of the pentose phosphate pathway. The purified xylitol dehydrogenase from G. mastotermitis was subjected to partial amino acid sequence analysis. The resulting amino acid information was then used to construct oligonucleotide probes for PCR amplification. The PCR product was used to screen a genomic library. The identified xdh gene includes one short intron at its 5' end. Putative regulatory signals were identified with the help of Saccharomyces cerevisiae regulatory sequence databases. An intronless xdh transcript, cloned by RT-PCR, was actively expressed in pBTac1 at 37 degrees C to approximately 8% of the soluble E. coli protein. Furthermore, the kinetic parameters were determined and conditions were found to stabilise the soluble and active protein.

X-ray structure determination of a vanadium-dependent haloperoxidase from Ascophyllum nodosum at 2.0 A resolution

The homo-dimeric structure of a vanadium-dependent haloperoxidase (V-BPO) from the brown alga Ascophyllum nodosum (EC 1.1.11.X) has been solved by single isomorphous replacement anomalous scattering (SIRAS) X-ray crystallography at 2.0 A resolution (PDB accession code 1QI9), using two heavy-atom datasets of a tungstate derivative measured at two different wavelengths. The protein sequence (SwissProt entry code P81701) of V-BPO was established by combining results from protein and DNA sequencing, and electron density interpretation. The enzyme has nearly an all-helical structure, with two four-helix bundles and only three small beta-sheets. The holoenzyme contains trigonal-bipyramidal coordinated vanadium atoms at its two active centres. Structural similarity to the only other structurally characterized vanadium-dependent chloroperoxidase (V-CPO) from Curvularia inaequalis exists in the vicinity of the active site and to a lesser extent in the central four-helix bundle. Despite the low sequence and structural similarity between V-BPO and V-CPO, the vanadium binding centres are highly conserved on the N-terminal side of an alpha-helix and include the proposed catalytic histidine residue (His418(V-BPO)/His404(V-CPO)). The V-BPO structure contains, in addition, a second histidine near the active site (His411(V-BPO)), which can alter the redox potential of the catalytically active VO2-O2 species by protonation/deprotonation reactions. Specific binding sites for the organic substrates, like indoles and monochlordimedone, or for halide ions are not visible in the V-BPO structure. A reaction mechanism for the enzymatic oxidation of halides is discussed, based on the present structural, spectroscopic and biochemical knowledge of vanadium-dependent haloperoxidases, explaining the observed enzymatic differences between both enzymes.

Right ventricular ischemia mimicking acute anterior myocardial infarction

Isolated right ventricular ischemia in combination with myocardial infarction (MI) is uncommon, accounting for fewer than 3% of all MI cases. A young man who presented with acute right ventricular ischemia from occlusion of a codominant right coronary artery proximal to an acute marginal branch is presented. His presenting electrocardiogram (ECG) showed ST segment elevation in V1 to V4 mimicking acute anterior MI. ECG criteria for isolated right ventricular ischemia are discussed.

Dual function of the selenoprotein PHGPx during sperm maturation

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) changes its physical characteristics and biological functions during sperm maturation. PHGPx exists as a soluble peroxidase in spermatids but persists in mature spermatozoa as an enzymatically inactive, oxidatively cross-linked, insoluble protein. In the midpiece of mature spermatozoa, PHGPx protein represents at least 50 percent of the capsule material that embeds the helix of mitochondria. The role of PHGPx as a structural protein may explain the mechanical instability of the mitochondrial midpiece that is observed in selenium deficiency.