1. HeAlth-data Register sTudies of Risk and Outcomes in Cardiac Surgery (HARTROCS)
ClinicalTrials.gov Identifier: NCT02276950
Collaborator and co-PI: Martin Holzmann
, Department of Emergency Medicine, Karolinska University Hospital, and Department of Internal Medicine, Karolinska Institutet, Stockholm, Sweden.
The aim of this research project is to study risks and outcomes in patients who undergoes cardiac surgery. We have established a fundament for the conduct of nationwide population-based studies by linking patient-level data from the Swedish Heart Surgery Register (SWEDEHEART
), the National Patient Register, the Cause of Death Register, the National Diabetes Register, the Swedish Renal Registry, the Prescribed Drug Register, and the 2nd version of the Swedish-Danish Scandinavian Donations and Transfusions database (SCANDAT2
). The project has received substantial research funding from the Swedish Heart-Lung Foundation, and other grant providers. Since 2013, we have published more than 35 original papers, and this is a currently active project under continuing development.
Main focus areas
The purpose of the research project is to increase our understanding of how common concurrent conditions, e.g. depression or diabetes, affect the perioperative risk and long-term prognosis in patients with heart disease who undergoes cardiac surgery. Through better understanding of these relationships, and estimations of their strength and independent contributions, we can improve patient care and clinical outcomes.
, as a diagnosis or co-morbidity before cardiac surgery – what are the implications? In a series of national population-based register-based studies, our research has explored the prevalence and consequences of depression in cardiac surgery patients. We have provided new insights regarding the role of socioeconomic factors in the relation between depression and prognosis in patients with ischemic heart disease, an aspect that was previously not adequately explored. We are evaluating the feasibility of a depression screening program in cardiac surgery, and forthcoming studies will address the longitudinal changes, and prognostic information that can be acquired from these data. These studies also contribute to our general understanding of the importance of patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs) in measuring the quality of care.
– Prior clinical trials in interventional treatment of coronary artery disease was almost exclusively conducted in patients with type 2 diabetes. By using data from the National Diabetes Register
, we are able to investigate a large cohort of patients with type 1 diabetes who underwent cardiac surgery, and thus provide new insights to guide clinical treatment recommendations in these patients.
Chronic kidney disease
and Acute kidney injury
- Dialysis-dependent renal disease is uncommon, but mild or moderate chronic kidney disease is very common in patients undergoing cardiac surgery. Acute kidney injury is also common following cardiac surgery and is associated with poor outcomes. No effective treatment or preventive measure for acute kidney injury exists at present, and the condition affects both patients with chronic kidney disease as well as patients without a history of renal impairment. Important findings from our research in this area is that also a very small and subclinical reduction of renal function worsen the long-term prognosis following cardiac surgery.
Risks associated with transfusion of blood products
- The SCANDAT2 database covers all data on blood donors, donations, components, transfusions and transfused patients in Sweden, dating back to the late 1960s. In collaboration with Gustaf Edgren
, Karolinska Institutet, we have linked data from SCANDAT2 and conducted a series of large epidemiological studies investigating different aspects of transfusion of blood products in relation to cardiac surgery.
2. Aortic valve replacement
Aortic valve replacement is one of the most commonly performed cardiac surgeries and is indicated in symptomatic patients with severe aortic stenosis or insufficiency, and in asymptomatic patients with reduced left ventricular systolic function or left ventricular dilatation. Aortic valve replacement is also indicated for treatment of infective endocarditis. The aortic valve can be replaced either by a biological or a mechanical valve prosthesis. The mechanical prosthesis has a long-lasting durability but require the use of life-long anticoagulant therapy (warfarin) whereas the biological prosthesis does not require the use of anticoagulants but has a limited durability. The choice between mechanical valves and bioprosthetic valves is dependent on factors such as expected survival and tolerance of anti-coagulation.
The overall aim of this project is to evaluate specific patient and prosthesis related aspects on long-term clinical outcomes after aortic valve replacement with a particular focus on bioprostheses. We will perform nationwide population-based cohort studies using data from SWEDEHEART enriched with information from other national health-data registers and quality registers. We expect that the results from this project will have direct implications for clinical decision making and patient care.
ABO blood group and risk of porcine bioprosthetic aortic valve degeneration
Limited data suggest an immune response in porcine to human xenografting. Some of the antigen epitopes in porcine grafts bear resemblance to human blood type antigens. This suggests that donor-recipient ABO mismatch might affect the attrition rate due to immune response. The clinical relevance in terms of prosthesis failure and survival are not known. The purpose of this project is to characterize the effect of patient blood type on porcine bioprosthetic valve failure after aortic valve replacement.
Clinical impact of prosthesis-patient mismatch in stented bioprosthetic aortic valve replacement
Prosthesis–patient mismatch is present when the effective orifice area of the inserted prosthetic valve is less than that of a normal human valve. This is a frequent problem in patients undergoing aortic valve replacement, and its main hemodynamic consequence is the generation of high transvalvular gradients through normally functioning prosthetic valves. The long-term clinical consequences are not clear in contemporary patient populations, and current evidence is inconclusive. The purpose of this project is to improve our understanding of the clinical impact of prosthesis–patient mismatch after aortic valve replacement.
Post market surveillance of prosthetic aortic heart valve models
In recent years there has been a shift in emphasis from establishing device safety and effectiveness before marketing to post market evidence generation and surveillance. A very important recent study from the UK signaled that two model of biological aortic valve prostheses displayed patterns of increased hazard. Swedish quality registers and health-data registers offer unparalleled opportunities to provide a proactive post market surveillance system. The purpose of this project is to study differences in long-term clinical outcomes (survival and freedom from reoperation) in bioprosthetic aortic valve models and to identify models that warrant further post market surveillance.
3. Prediction models for survival in heart failure
In collaboratoration with Lars Lund, Karolinska Institutet.
Prediction models help clinicians to assess prognosis in heart failure which is important when selecting advanced treatment options such as cardiac resynchronization therapy, left ventricular assist device therapy, or heart transplantation.
- Well-known models (e.g. Seattle Heart Failure Model) in new patient populations.
- Recently developed models (e.g. MAGGIC score) in different patient populations for the purpose of validation.
4. Heart rhythm and rate in heart failure
In collaboratoration with Lars Lund, Karolinska Institutet.
In this large-scale registry-based research project, data from the Swedish Heart Failure Register (SwedeHF
) was enriched with patient-level data from other national Swedish registers (e.g. the National Patient Register, and the Cause of Death Register), and is used to perform comprehensive and comparative assessments of prevalence, associations, and prognostic role of heart rhythm and rate in heart failure patients with different levels of ejection fraction.
5. National register studies in thoracic surgery
ClinicalTrials.gov Identifier: NCT03567538
In analogy to the HARTROCS project described above, this project will establish a basis for the conduct of nationwide population-based studies in general thoracic surgery by linking patient-level data from the Swedish Thoracic Surgery Register (ThoR)
and other national health-data registers. All centers in Sweden that perform thoracic surgery report to the register. One PhD-student and one postdoc is currently developing the research program within this project, and the following sub-studies are ongoing:
- Pulmonary metastasectomy in colorectal cancer – prognostic factors
- Validation of risk models for prediction of early mortality after lung resections
- Minimally invasive vs open thoracotomy lobectomy in lung cancer
Forthcoming studies will explore the importance of socioeconomic factors and regional differences in utilization of surgical treatment of lung cancer.