Disparities in PCV impact between different ethnic populations cohabiting in the same region: A systematic review of the literature

Novel coenzyme Q6 genetic variant increases susceptibility to pneumococcal disease

Acute lower respiratory tract infection (ALRI) remains a major worldwide cause of childhood mortality, compelling innovation in prevention and treatment. Children in Papua New Guinea (PNG) experience profound morbidity from ALRI caused by Streptococcus pneumoniae. As a result of evolutionary divergence, the human PNG population exhibits profound genetic variation and diversity. To address unmet health needs of children in PNG, we tested whether genetic variants increased ALRI morbidity. Whole-exome sequencing of a pilot child cohort identified homozygosity for a novel single-nucleotide variant (SNV) in coenzyme Q6 (COQ6) in cases with ALRI. COQ6 encodes a mitochondrial enzyme essential for biosynthesis of ubiquinone, an electron acceptor in the electron transport chain. A significant association of SNV homozygosity with ALRI was replicated in an independent ALRI cohort (P = 0.036). Mice homozygous for homologous mouse variant Coq6 exhibited increased mortality after pneumococcal lung infection, confirming causality. Bone marrow chimeric mice further revealed that expression of variant Coq6 in recipient (that is, nonhematopoietic) tissues conferred increased mortality. Variant Coq6 maintained ubiquinone biosynthesis, while accelerating metabolic remodeling after pneumococcal challenge. Identification of this COQ6 variant provides a genetic basis for increased pneumonia susceptibility in PNG and establishes a previously unrecognized role for the enzyme COQ6 in regulating inflammatory-mediated metabolic remodeling.

Jerusalem's CoVID-19 Experience-The Effect of Ethnicity on Disease Prevalence and Adherence to Testing

BACKGROUND

The management of the SARS-CoV-2 pandemic depends amongst other factors on disease prevalence in the general population. The gap between the true rate of infection and the detected rate of infection may vary, especially between sub-groups of the population. Identifying subpopulations with high rates of undetected infection can guide authorities to direct resource distribution in order to improve health equity.

METHODS

A cross-sectional epidemiological survey was conducted between April and July 2021 in the Pediatric Emergency Department of the Shaare Zedek Medical Center, Jerusalem, Israel. We compared three categories: unconfirmed disease (UD), positive serology test result with no history of positive PCR; confirmed disease (CD), history of a positive PCR test result, regardless of serology test result; and no disease (ND), negative serology and no history of PCR. These categories were applied to local prevailing subpopulations: ultra-orthodox Jews (UO), National Religious Jews (NRJ), secular Jews (SJ), and Muslim Arabs (MA).

RESULTS

Comparing the different subpopulations groups, MAs and UOs had the greatest rate of confirmed or unconfirmed disease. MA had the highest rate of UD and UO had the highest rate of CD. UD significantly correlated with ethnicity, with a low prevalence in NRJ and SJ. UD was also associated with larger family size and housing density defined as family size per number of rooms.

CONCLUSION

This study highlights the effect of ethnicity on disease burden. These findings should serve to heighten awareness to disease burden in weaker populations and direct a suitable prevention program to each subpopulation's needs. Early awareness and possible intervention may lower morbidity and mortality.

Effectiveness of the 10-valent pneumococcal conjugate vaccine on pediatric pneumonia confirmed by ultrasound: a matched case-control study

Background

Bangladesh introduced the 10-valent pneumococcal conjugate vaccine (PCV10) for children aged < 1 year in March 2015. Previous vaccine effectiveness (VE) studies for pneumonia have used invasive pneumococcal disease or chest X-rays. None have used ultrasound. We sought to determine the VE of PCV10 against sonographically-confirmed pneumonia in three subdistrict health complexes in Bangladesh.

Methods

We conducted a matched case–control study between July 2015 and September 2017 in three subdistricts of Sylhet, Bangladesh. Cases were vaccine-eligible children aged 3–35 months with sonographically-confirmed pneumonia, who were matched with two types of controls by age, sex, week of diagnosis, subdistrict health complex (clinic controls) or distance from subdistrict health complex (community controls) and had an illness unlikely due to Streptococcus pneumoniae (clinic controls) or were healthy (community controls). VE was measured using multivariable conditional logistic regression.

Results

We evaluated 8926 children (average age 13.3 months, 58% boys) with clinical pneumonia by ultrasound; 2470 had pneumonia with consolidations ≥ 1 cm; 1893 pneumonia cases were matched with 4238 clinic controls; and 1832 were matched with 3636 community controls. VE increased with the threshold used for consolidation size on ultrasound: the adjusted VE of ≥ 2 doses vs. non-recipients of PCV10 against pneumonia increased from 15.8% (95% CI 1.6–28.0%) for consolidations ≥ 1 cm to 29.6% (12.8–43.2%) for consolidations ≥ 1.5 cm using clinic controls and from 2.7% (− 14.2–17.2%) to 23.5% (4.4–38.8%) using community controls, respectively.

Conclusions

PCV10 was effective at reducing sonographically-confirmed pneumonia in children aged 3–35 months of age when compared to unvaccinated children. VE increased with the threshold used for consolidation size on ultrasound in clinic and community controls alike. This study provides evidence that lung ultrasound is a useful alternative to chest X-ray for case–control studies evaluating the effectiveness of vaccines against pneumonia.

Effectiveness of Pneumococcal Vaccines on Otitis Media in Children: A Systematic Review

OBJECTIVES

We aimed to determine the effectiveness of pneumococcal vaccines on otitis media (OM) and acute otitis media (AOM) in children.

METHODS

We conducted a systematic search in databases PubMed (MEDLINE), Embase, Lilacs, and Web of Science. We included observational studies that evaluated any pneumococcal vaccine - including 7, 10, and 13-valent pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13) and 23-valent polysaccharide vaccines (PPSV23) as the intervention, in children aged less than five years.

RESULTS

Out of the 2112 screened studies, 48 observational studies complied with the eligibility criteria and therefore were included in this review. Of the included studies, 30 (63%) were before-after, eleven (23%) cohort, six (13%) time series, and one (2%) case-control study designs. Vaccine effectiveness (VE) in preventing OM or AOM varied by vaccine type. In children under 24 months VE ranged from 8% and 42.7% (PCV7), 5.6% to 84% (PCV10) and 2.2% to 68% (PCV13). In children aged less than 60 months, VE ranged between 13.2% and 39% for PCV7, 11% to 39% for PCV10 (only children under 48 months), and 39% to 41% (PCV13).

CONCLUSIONS

Our results demonstrate significant effect of pneumococcal vaccination in decreasing OM or AOM in children under five years old in several countries supporting the public health value of introducing PCVs in national immunization programs.

Impact of national introduction of ten-valent pneumococcal conjugate vaccine on invasive pneumococcal disease in Bangladesh: Case-control and time-trend studies

BACKGROUND

Bangladesh introduced the ten-valent pneumococcal conjugate vaccine (PCV10) into its national immunization program in March 2015 creating an opportunity to assess the real-world impact of PCV on invasive pneumococcal disease (IPD).

METHODS

Between January 2014 and June 2018, children aged 3-35 months in three rural sub-districts of Sylhet district of Bangladesh were visited every two months to collect morbidity and care-seeking data. Children attending sub-district hospitals with pneumonia, meningitis, or sepsis were assessed for IPD after obtaining informed consent. Blood and cerebrospinal fluid were collected from enrolled children to isolate pneumococcus using culture and molecular test. Children who were age-eligible to receive the PCV and had pneumococcus isolated were enrolled as cases. Four age and sex-matched clinic and community controls were selected for each case within one to two weeks of case identification. Data on immunization status and confounders were collected. PCV coverage was estimated using vaccine coverage surveys. Case-control and incidence trend analyses were conducted to assess the impact of PCV on IPD.

RESULTS

The community cohort yielded 217,605 child years of observations and 154,773 sick child-visits to study hospitals. Pneumococcus was isolated from 44 children who were age-eligible to receive PCV; these children were enrolled as cases. The cases were matched with 166 community- and 150 clinic-controls. The matched case-control analyses using community-controls showed 83% effectiveness (95% CI: 1.57-97.1%) and clinic controls showed 90% effectiveness (95% CI: -26.0% to 99.1%) of PCV in preventing IPD. Incidence trend analysis estimated vaccine effectiveness at 80.1% (95% CI: 38.4, 93.6).

CONCLUSION

PCV in this pediatric population in Bangladesh was highly effective in preventing IPD.

Predictors of antibody persistence to the 7-valent pneumococcal conjugate vaccine in healthy Fijian infants at 12 months of age

Little is known about the predictors of antibody persistence to pneumococcal conjugate vaccines (PCV) in the context of reduced dose schedules. In Fiji, an RCT investigated 0, 1, 2 and 3 dose schedules of 7-valent PCV administered at 6, 10 and 14 weeks of age in 364 healthy infants. This study was a post-hoc analysis of the predictors of poor antibody persistence at 12 months, prior to a booster, using univariable and multivariable analyses. The strongest predictors of poor antibody persistence as measured by serotype-specific immunoglobulin G (IgG) and opsonophagocytosis (OI) assays were being of Indigenous Fijian ethnicity (IgG: adjusted odds ratio (aOR) 3.43, p < 0.001; OI: aOR 1.96, p = 0.013) and receipt of fewer than 3 doses of PCV. These findings may help to identify which children may be at an increased risk of pneumococcal disease in the context of reduced dose primary series PCV schedules.

Pneumococcal Conjugate Vaccines Turning the Tide on Inequity: A Retrospective Cohort Study of New Zealand Children Born 2006-2015

BACKGROUND

Hospitalization rates for infectious diseases in New Zealand (NZ) children have increased since 1989. The highest burden is among Māori and Pacific children, and the most socioeconomically deprived. New Zealand introduced pneumococcal conjugate vaccine (PCV)7 in June 2008, PCV10 in 2011, and PCV13 in 2014.

METHODS

A retrospective cohort study of NZ children aged <6 years between 2006 and 2015 was performed using administrative databases. Demographics and hospitalizations were linked to evaluate the impact of the PCV vaccination program on cases of invasive pneumococcal disease (IPD), all-cause pneumonia (ACP), and otitis media (OM), defined by ICD-10-AM codes, and to explore the effect by ethnicity and deprivation.

RESULTS

Between 2006 and 2015, there were 640 children hospitalized with IPD, 26589 for ACP, and 44545 for OM. IPD hospitalizations declined by 73% between 2005 and 2015 for children <6 years of age, whereas ACP and OM declined by 8% and 25%, respectively. The highest rates for all diseases were among Māori and Pacific children and those from high deprivation. However, the declines were highest among Māori and Pacific children and those from socioeconomically deprived areas. IPD hospitalizations declined by 79% and 67% for Māori and Pacific children, respectively, between 2006 and 2015. ACP declined by 12% in Māori and 21% in Pacific children. OM declined by 51% in Māori children.

CONCLUSION

In contrast to the increasing trend of hospitalization rates for infectious disease in New Zealand, the use of PCV appears associated with reductions in ethnic and socioeconomic disparities in hospitalization for IPD, ACP, and OM.

Impact of pneumococcal conjugate vaccines on hospitalizations for pneumonia in the United States

INTRODUCTION

Pneumonia is one of the leading causes of morbidity and mortality among children and older adults. Pneumococcal conjugate vaccines (PCVs) were introduced into the US routine infant vaccination schedule leading to substantial reductions of invasive pneumococcal diseases (IPD). PCV introduction also led to reductions in all-cause pneumonia among US children, though the indirect impact of PCVs on pneumonia in adults is difficult to quantify, especially due to the recent US recommendation for direct PCV use in older adults. Areas covered: We described the existing evidence for both the direct and indirect impact of PCVs on pneumonia among children and adults in the US since PCV introduction. Expert commentary: The introduction of PCVs into the US routine infant vaccination schedule led to important reductions in the burden of IPD and non-invasive pneumonia among vaccinated and unvaccinated populations. The impact of direct vaccination of older adults in the US since 2014, though difficult to quantify, is currently being evaluated. As pneumonia remains one of the leading causes of morbidity and mortality in the US, future evaluations of the direct and indirect effects of current and expanded valency PCVs in the US population are needed.

Streptococcus pneumoniae Cell Wall-Localized Trigger Factor Elicits a Protective Immune Response and Contributes to Bacterial Adhesion to the Host

Trigger factor (TF) has a known cytoplasmic function as a chaperone. In a previous study we showed that pneumococcal TF is also cell-wall localized and this finding combined with the immunogenic characteristic of TF, has led us to determine the vaccine potential of TF and decipher its involvement in pneumococcal pathogenesis. Bioinformatic analysis revealed that TF is conserved among pneumococci and has no human homologue. Immunization of mice with recombinant (r)TF elicited a protective immune response against a pneumococcal challenge, suggesting that TF contributes to pneumococcal pathogenesis. Indeed, rTF and an anti-rTF antiserum inhibited bacterial adhesion to human lung derived epithelial cells, indicating that TF contributes to the bacterial adhesion to the host. Moreover, bacteria lacking TF demonstrated reduced adhesion, in vitro, to lung-derived epithelial cells, neural cells and glial cells. The reduced adhesion could be restored by chromosomal complementation. Furthermore, bacteria lacking TF demonstrated significantly reduced virulence in a mouse model. Taken together, the ability of rTF to elicit a protective immune response, involvement of TF in bacterial adhesion, conservation of the protein among pneumococcal strains and the lack of human homologue, all suggest that rTF can be considered as a future candidate vaccine with a much broader coverage as compared to the currently available pneumococcal vaccines.

Epidemiology of invasive pneumococcal disease in indigenous and non-indigenous adults in northwestern Ontario, Canada, 2006-2015

BACKGROUND

Despite the use of pneumococcal vaccines, indigenous populations are consistently disproportionately affected by invasive pneumococcal disease (IPD). With recent changes in Ontario's provincial pneumococcal vaccination program, we sought to evaluate the epidemiology and burden of IPD in northwestern Ontario (NWO) Canada - a region that contains a substantial (19.2%) indigenous population.

METHODS

We retrospectively reviewed all adult cases of IPD that were reported to the Thunder Bay District Health Unit, in Thunder Bay, Ontario, Canada, over a 10-year period (2006-2015). Patients admitted to the Thunder Bay Regional Health Sciences Centre with IPD had their charts reviewed to abstract clinical data. Statistical analysis, including incidence rates of IPD, was performed.

RESULTS

Two hundred sixty-two cases of IPD occurred over the 10-year observation period and clinical data was available for 182 cases. Fifty-three of 182 (29.1%) patients were indigenous. 73 of 182 (40.1%) of patients were immunocompromised. Indigenous patients with IPD were more likely to be immunocompromised than non-indigenous patients (p < 0.001). Serotype data was available for 159 cases of IPD; PCV7, PCV13, and PPV23 covered 5.7%, 28.3%, and 79.2% of isolates, respectively, while 29 (20.8%) were non-vaccine serotypes. The annual incidence rate of IPD ranged from 8.9 to 25.9 per 100,000 among adults 18-64 years old; among adults 65 years of age and older the annual incidence of IPD ranged from 18.5 to 60.7 per 100,000.

CONCLUSION

Among adults in NWO, Canada, there is a high incidence of IPD. Immunocompromised indigenous adults in NWO may benefit from pneumococcal vaccination coverage. Emerging non-vaccine serotypes of Streptococcus pneumoniae warrant the consideration of the provincial pneumococcal vaccination program.

Effect of ten-valent pneumococcal conjugate vaccine introduction on pneumococcal carriage in Fiji: results from four annual cross-sectional carriage surveys

BACKGROUND

The indirect effects of pneumococcal conjugate vaccines (PCVs) are mediated through reductions in carriage of vaccine serotypes. Data on PCVs in Asia and the Pacific are scarce. Fiji introduced the ten-valent PCV (PCV10) in 2012, with a schedule consisting of three priming doses at 6, 10, and 14 weeks of age and no booster dose (3 + 0 schedule) without catch-up. We investigated the effects of PCV10 introduction using cross-sectional nasopharyngeal carriage surveys.

METHODS

We did four annual carriage surveys (one pre-PCV10 and three post-PCV10) in the greater Suva area in Fiji, during 2012-15, of 5-8-week-old infants, 12-23-month-old children, 2-6-year-old children, and their caregivers (total of 8109 participants). Eligible participants were of appropriate age, had axillary temperature lower than 37°C, and had lived in the community for at least 3 consecutive months. We used purposive quota sampling to ensure a proper representation of the Fiji population. Pneumococci were detected by real-time quantitative PCR, and molecular serotyping was done with microarray.

FINDINGS

3 years after PCV10 introduction, vaccine-serotype carriage prevalence declined, with adjusted prevalences (2015 vs 2012) of 0·56 (95% CI 0·34-0·93) in 5-8-week-old infants, 0·34 (0·23-0·49) in 12-23-month-olds, 0·47 (0·34-0·66) in 2-6-year-olds, and 0·43 (0·13-1·42) in caregivers. Reductions in PCV10 serotype carriage were evident in both main ethnic groups in Fiji; however, carriage of non-PCV10 serotypes increased in Indigenous Fijian infants and children. Density of PCV10 serotypes and non-PCV10 serotypes was lower in PCV10-vaccinated children aged 12-23 months than in PCV10-unvaccinated children of the same age group (PCV10 serotypes -0·56 [95% CI -0·98 to -0·15], p=0·0077; non-PCV10 serotypes -0·29 [-0·57 to -0·02], p=0·0334).

INTERPRETATION

Direct and indirect effects on pneumococcal carriage post-PCV10 are likely to result in reductions in pneumococcal disease, including in infants too young to be vaccinated. Serotype replacement in carriage in Fijian children, particularly Indigenous children, warrants further monitoring. Observed changes in pneumococcal density might be temporal rather than vaccine related.

FUNDING

Department of Foreign Affairs and Trade of the Australian Government through the Fiji Health Sector Support Program; Victorian Government's Operational Infrastructure Support Program; Bill & Melinda Gates Foundation.

Development and validation of a search filter to identify equity-focused studies: reducing the number needed to screen

Background

Health inequalities, worse health associated with social and economic disadvantage, are reported by a minority of research articles. Locating these studies when conducting an equity-focused systematic review is challenging due to a deficit in standardised terminology, indexing, and lack of validated search filters. Current reporting guidelines recommend not applying filters, meaning that increased resources are needed at the screening stage.

Methods

We aimed to design and test search filters to locate studies that reported outcomes by a social determinant of health. We developed and expanded a ‘specific terms strategy’ using keywords and subject headings compiled from recent systematic reviews that applied an equity filter. A ‘non-specific strategy’ was compiled from phrases used to describe equity analyses that were reported in titles and abstracts, and related subject headings. Gold standard evaluation and validation sets were compiled. The filters were developed in MEDLINE, adapted for Embase and tested in both. We set a target of 0.90 sensitivity (95% CI; 0.84, 0.94) in retrieving 150 gold standard validation papers. We noted the reduction in the number needed to screen in a proposed equity-focused systematic review and the proportion of equity-focused reviews we assessed in the project that applied an equity filter to their search strategy.

Results

The specific terms strategy filtered out 93-95% of all records, and retrieved a validation set of articles with a sensitivity of 0.84 in MEDLINE (0.77, 0.89), and 0.87 (0.81, 0.92) in Embase. When combined (Boolean ‘OR’) with the non-specific strategy sensitivity was 0.92 (0.86, 0.96) in MEDLINE (Embase 0.94; 0.89, 0.97). The number needed to screen was reduced by 77% by applying the specific terms strategy, and by 59.7% (MEDLINE) and 63.5% (Embase) by applying the combined strategy. Eighty-one per cent of systematic reviews filtered studies by equity.

Conclusions

A combined approach of using specific and non-specific terms is recommended if systematic reviewers wish to filter studies for reporting outcomes by social determinants. Future research should concentrate on the indexing standardisation for equity studies and further development and testing of both specific and non-specific terms for accurate study retrieval.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0567-x) contains supplementary material, which is available to authorized users.

Invasive pneumococcal disease in Northern Alberta, not a Red Queen but a dark horse

BACKGROUND

The consequences of the introduction of various pneumococcal protein conjugate vaccines (PCV) for children and adults is poorly understood.

OBJECTIVE

We undertook a population-based cohort study of invasive pneumococcal disease (IPD) in Northern Alberta (Canada) from 2000 to 2014, years spanning pre-and early PCV (2000-2004) vs PCV-7 (2005-2009) vs PCV-13 (2010-2014) time periods.

DESIGN

We collected clinical, laboratory, and Streptococcus pneumoniae serotype information on all patients from 2000 to 2014. We determined changes in presentation, outcomes, serotypes, and incidence in children and adults across time periods.

SETTING

There were 509 cases of IPD in children, an 80% decrease over time. Rates of empyema (4.0-15.7%, p < 0.001), ICU admission (13.1-20%), and mortality (1.8-8.4%, p < 0.001) increased over time. There were 2417 cases of IPD in adults. Unlike children, incidence of IPD did not change nor did rates of empyema. ICU admissions increased (p = 0.004) and mortality decreased (18.7-16.5%, p = 0.002). The total number of serotypes causing IPD remained stable in children (22 vs 26 vs 20) while they decreased in adults (49 vs 47 vs 42).

CONCLUSIONS AND RELEVANCE

For children, PCV vaccination strategies resulted in decreased overall rates of IPD and we observed increased rates of empyema and mortality; for adults, there was no change in IPD rates although disease severity increased while mortality decreased. On a population-wide basis, our results suggest that current PCV vaccination strategies are associated with an overall decrease in IPD but disease severity seems to be increasing in both children and adults.

Barriers, supports, and effective interventions for uptake of human papillomavirus- and other vaccines within global and Canadian Indigenous peoples: a systematic review protocol

BACKGROUND

Despite the existence of human papilloma virus (HPV) vaccines with demonstrated safety and effectiveness and funded HPV vaccination programs, coverage rates are persistently lower and cervical cancer burden higher among Canadian Indigenous peoples. Barriers and supports to HPV vaccination in Indigenous peoples have not been systematically documented, nor have interventions to increase uptake in this population. This protocol aims to appraise the literature in Canadian and global Indigenous peoples, relating to documented barriers and supports to vaccination and interventions to increase acceptability/uptake or reduce hesitancy of vaccination. Although HPV vaccination is the primary focus, we anticipate only a small number of relevant studies to emerge from the search and will, therefore, employ a broad search strategy to capture literature related to both HPV vaccination and vaccination in general in global Indigenous peoples.

METHODS

Eligible studies will include global Indigenous peoples and discuss barriers or supports and/or interventions to improve uptake or to reduce hesitancy, for the HPV vaccine and/or other vaccines. Primary outcomes are documented barriers or supports or interventions. All study designs meeting inclusion criteria will be considered, without restricting by language, location, or data type. We will use an a priori search strategy, comprised of key words and controlled vocabulary terms, developed in consultation with an academic librarian, and reviewed by a second academic librarian using the PRESS checklist. We will search several electronic databases from date of inception, without restrictions. A pre-defined group of global Indigenous websites will be reviewed for relevant gray literature. Bibliographic searches will be conducted for all included studies to identify relevant reviews. Data analysis will include an inductive, qualitative, thematic synthesis and a quantitative analysis of measured barriers and supports, as well as a descriptive synthesis and quantitative summary of measures for interventions.

DISCUSSION

To our knowledge, this study will contribute the first systematic review of documented barriers, supports, and interventions for vaccination in general and for HPV vaccination. The results of this study are expected to inform future research, policies, programs, and community-driven initiatives to enhance acceptability and uptake of HPV vaccination among Indigenous peoples.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO Registration Number: CRD42017048844.

Invasive Pneumococcal Disease: Still Lots to Learn and a Need for Standardized Data Collection Instruments

Background. Large studies of invasive pneumococcal disease (IPD) are frequently lacking detailed clinical information. Methods. A population-based 15-year study of IPD in Northern Alberta. Results. 2435 patients with a mean age of 54.2 years formed the study group. Males outnumbered females and Aboriginal and homeless persons were overrepresented. High rates of smoking, excessive alcohol use, and illicit drug use were seen. Almost all (87%) had a major comorbidity and 15% had functional limitations prior to admission. Bacteremia, pneumonia, and meningitis were the most common major manifestations of IPD. Almost half of the patients had alteration of mental status at the time of admission and 22% required mechanical ventilation. Myocardial infarction, pulmonary embolism, and new onset stroke occurred in 1.7, 1.3, and 1.1% of the patients, respectively; of those who had echocardiograms, 35% had impaired ventricular function. The overall in-hospital mortality was 15.6%. Conclusions. IPD remains a serious infection in adults. In addition to immunization, preventative measures need to consider the sociodemographic features more carefully. A standard set of data need to be collected so that comparisons can be made from study to study. Future investigations should target cardiac function and pulmonary embolism prevention in this population.