Paradigm shifts in cardiovascular medicine

Biomechanics of Transcatheter Aortic Valve Implant

Transcatheter aortic valve implantation (TAVI) has grown exponentially within the cardiology and cardiac surgical spheres. It has now become a routine approach for treating aortic stenosis. Several concerns have been raised about TAVI in comparison to conventional surgical aortic valve replacement (SAVR). The primary concerns regard the longevity of the valves. Several factors have been identified which may predict poor outcomes following TAVI. To this end, the lesser-used finite element analysis (FEA) was used to quantify the properties of calcifications which affect TAVI valves. This method can also be used in conjunction with other integrated software to ascertain the functionality of these valves. Other imaging modalities such as multi-detector row computed tomography (MDCT) are now widely available, which can accurately size aortic valve annuli. This may help reduce the incidence of paravalvular leaks and regurgitation which may necessitate further intervention. Structural valve degeneration (SVD) remains a key factor, with varying results from current studies. The true incidence of SVD in TAVI compared to SAVR remains unclear due to the lack of long-term data. It is now widely accepted that both are part of the armamentarium and are not mutually exclusive. Decision making in terms of appropriate interventions should be undertaken via shared decision making involving heart teams.

Bioimpedance Sensing of Implanted Stent Occlusions: Smart Stent

Coronary artery disease is one of the most common diseases in developed countries and affects a large part of the population of developing countries. Preventing restenosis in patients with implanted stents is an important current medical problem. The purpose of this work is to analyse the viability of bioimpedance sensing to detect the formation of atheromatous plaque in an implantable stent. Simulations in COMSOL Multiphysics were performed to analyse the performance of the proposed bioimpedance sensing system, based on the Sheffield technique. Both non-pathological and pathological models (with atheromatous plaque), including the flow of blood were considered. Simulations with the non-pathological model showed a homogeneous distribution of the measured current intensity in the different electrodes, for every configuration. On the other hand, simulations with the pathological model showed a significant decrease of the measured current intensity in the electrodes close to the simulated atheromatous plaque. The presence of the atheromatous plaque can, therefore, be detected by the system with a simple algorithm, avoiding the full reconstruction of the image and the subsequent computational processing requirements.

Structural Heart Valve Disease in the Era of Change and Innovation: The Crosstalk between Medical Sciences and Engineering

In recent years, both cardiology and cardiovascular surgery have witnessed an era of consistently evolving changes which have dramatically transformed the course and management of cardiovascular disease [...].

The Use of Bioactive Polymers for Intervention and Tissue Engineering: The New Frontier for Cardiovascular Therapy

Coronary heart disease remains one of the leading causes of death in most countries. Healthcare improvements have seen a shift in the presentation of disease with a reducing number of ST-segment elevation myocardial infarctions (STEMIs), largely due to earlier reperfusion strategies such as percutaneous coronary intervention (PCI). Stents have revolutionized the care of these patients, but the long-term effects of these devices have been brought to the fore. The conceptual and technologic evolution of these devices from bare-metal stents led to the creation and wide application of drug-eluting stents; further research introduced the idea of polymer-based resorbable stents. We look at the evolution of stents and the multiple advantages and disadvantages offered by each of the different polymers used to make stents in order to identify what the stent of the future may consist of whilst highlighting properties that are beneficial to the patient alongside the role of the surgeon, the cardiologist, engineers, chemists, and biophysicists in creating the ideal stent.

Exploring patient-reported outcomes following percutaneous coronary intervention: A qualitative study

BACKGROUND

Percutaneous coronary intervention (PCI) is a common cardiac procedure used to treat obstructive coronary artery disease. Patient-centred care is a priority in cardiovascular health having been shown to increase patient satisfaction, engagement with rehabilitation activities and reduce anxiety. Evidence indicates that patient-centred care is best achieved by routine collection of patient-reported outcomes (PROs). However, existing patient-reported outcome measures (PROMs) have limited the patient involvement in their development.

AIMS

To identify and explore outcomes, patients perceive as important following PCI.

METHODS

A qualitative design was adopted. Eight focus groups and five semi-structured interviews were conducted with 32 patients who had undergone PCI in the previous 6 months. Outcomes were identified and mapped under the U.S. Food and Drug Administration (FDA) patient-reported outcome (PROs) domains of feeling (physical and psychological outcomes), function and evaluation. Inductive and deductive analysis methods were used with open, axial and thematic coding.

RESULTS

Consistent with prior studies, patients identified feeling and function outcomes such as reductions in physical and psychological symptoms and the ability to perform usual activities as important. Participants also identified a range of new outcomes, including confidence to return to usual activities and evaluation domains such as adverse effects of medications and the importance of patient communication.

CONCLUSION

The findings of this research should be considered in the design of a cardiac PROM for PCI patients. A PROM which adequately assesses these outcomes can provide clinicians and hospital staff with a foundation in which to address these concerns or symptoms.

Disparity in drug-eluting stent utilization by insurance type

BACKGROUND

Because of the expense of drug-eluting stents (DES) and associated adjuvant therapy, nonclinical, socioeconomic factors may be associated with DES use in clinical practice.

METHODS

Data on 112,588 patients from the National Cardiovascular Data CathPCI Registry (NCDR) between 2004 and 2005 with "on-label" indications for DES were analyzed. Insurance status was categorized as No Insurance, Governmental, and Private Insurance. Hierarchical multivariable logistic regression analyses were used to evaluate the association between insurance status and DES use, after adjusting for patient and procedural characteristics.

RESULTS

Drug-eluting stent use was >96% during the study period, with utilization significantly associated with insurance status. Compared with patients with Private Insurance, patients with No Insurance (odds ratio 0.44, 95% confidence interval 0.37-0.53) and Government Insurance (odds ratio 0.73, 95% confidence interval 0.67-0.80) were significantly less likely to receive a DES than a bare metal stent. Repeat analysis of patients <65 years of age demonstrated virtually identical results.

CONCLUSIONS

Despite the high penetration of DES, significant associations between insurance status and DES utilization were identified. This indicates that disparities in health care based on socioeconomic factors extend to DES utilization and highlights the need to address such disparities as novel therapies emerge.

Cost comparison of four revascularisation procedures for the treatment of multivessel coronary artery disease

OBJECTIVE

An economic evaluation was performed, using modelling techniques, to compare 1-year total costs of four revascularisation procedures in patients with multivessel disease: on-pump coronary artery bypass grafting (CABG); off-pump CABG; percutaneous coronary intervention (PCI) with bare-metal stents (BMS); and PCI with drug-eluting stents (DES).

METHODS

Clinical data were derived from four randomised clinical trials comparing CABG versus PCI, as well as from literature reviews. Resource use and unit cost estimates were modelled to reflect current Canadian practice.

RESULTS

This study demonstrated that 1 year after the initial revascularisation, PCI with BMS is the least costly procedure, followed by off-pump CABG, PCI with DES and on-pump CABG. DES became the most costly procedure if 3.5 or more DES were used or if staged PCI was performed.

Adverse clinical events in patients treated with sirolimus-eluting stents: the impact of Type D personality

BACKGROUND

Little is known about the impact of psychological risk factors on cardiac prognosis in the drug-eluting stent era. We examined whether the distressed personality (Type D) moderates the effect of percutaneous coronary intervention with sirolimus-eluting stent implantation on adverse clinical events at 2-year follow-up. Type D is an emerging risk factor in patients with cardiovascular disease.

DESIGN

Prospective follow-up study.

METHODS

Three hundred and fifty-eight patients with ischemic heart disease, who consecutively underwent percutaneous coronary intervention with sirolimus-eluting stent as part of the Rapamycin-Eluting Stent Evaluated At Rotterdam Cardiology Hospital registry, completed the Type D Scale (DS14) post-percutaneous coronary intervention (PCI). The end-point was a composite of death and non-fatal myocardial infarction 2 years after PCI.

RESULTS

At follow-up, there were 22 events (12 deaths and 11 myocardial infarctions). Type D patients had a greater than two-fold risk of an event at follow-up compared with non-Type D patients (10.4 vs. 4.4%, P=0.031). In multivariable analysis, Type D remained an independent predictor of adverse outcome (hazard ratio: 2.61; 95% confidence interval: 1.12-6.09; P=0.027) adjusting for sex, age, and history of coronary artery disease, multivessel disease, diabetes, hypercholesterolemia, hypertension, renal impairment and smoking. Previous cardiac history was also an independent predictor of death or myocardial infarction (hazard ratio: 2.83; 95% confidence interval: 1.00-7.96; P=0.049).

CONCLUSIONS

Type D personality moderated the effect of percutaneous coronary intervention on hard clinical events despite treatment with the latest innovation in interventional cardiology. The inclusion of psychological risk factors in general and personality factors in particular may optimize risk stratification in the drug-eluting stent era.

Initial impact of drug-eluting stent use on the spectrum of patients undergoing percutaneous coronary intervention

BACKGROUND

The availability of drug-eluting stents was expected to expand the application of percutaneous coronary intervention to a wider group of patients and lesion types. We sought to determine whether drug-eluting stents' availability has changed the practices of operators performing percutaneous coronary intervention with regard to patient selection and procedural factors.

METHODS

We compared the clinical and angiographic characteristics of patients who underwent percutaneous coronary intervention at the Methodist Hospital, Houston, Texas, during three periods: June 2002-March 2003, June 2003-March 2004 and June 2004-March 2005. Sirolimus-eluting stents were available during the latter two periods. Paclitaxel eluting stents became available during the third period.

RESULTS

A greater proportion of patients undergoing diagnostic catheterization were referred for percutaneous coronary intervention during the latter two periods (26.8%, 30.4%, 30.4%, respectively, P<0.0001). Patients undergoing stent placement during the latter two periods were more likely to have hypertension, hyperlipidemia or to have undergone previous percutaneous coronary intervention. The average implanted stent length was greater during the latter periods (14.5+/-4.6, 16.4+/-5.2, 16.8+/-5.5 mm, respectively, P<0.0001) and the average stent diameter was smaller (3.23+/-1.22, 3.13+/-1.16, 3.02+/-0.6 mm, respectively, P<0.0001). The frequency of percutaneous coronary intervention involving long lesions (>20 mm) and Left Anterior Descending (LAD) lesions was higher in the latter two periods and the frequency of multivessel stenting was higher in the last period.

CONCLUSIONS

The spectrum of patients and coronary lesions that have undergone stenting has changed, particularly in the third period when both drug-eluting stent types were available. We observed a gradual shift toward higher-risk clinical and lesion characteristics following the introduction of drug-eluting stents.

High Mortality Associated With Precluded Coronary Artery Bypass Surgery Caused by Severe Distal Coronary Artery Disease

Background— Patients with extensive coronary artery disease (CAD) have better prognosis when treated with coronary artery bypass grafting surgery (CABG), especially when left ventricular dysfunction (LVD) is present. However, there are scanty data about the clinical course of patients not referred to CABG because of extensive and severe atherosclerotic involvement of distal coronary arteries (ENDCAD). The aim of this study was to evaluate patients with multivessel (MV) or left main CAD (LM) who had CABG precluded because of ENDCAD.

Methods and Results— Between August 1999 and July 2001, 51 patients who had clinical indication but were not eligible for CABG because of ENDCAD were followed for at least 12 months or until death. There were 32 men and 19 women (age 61±9 years). Previous acute myocardial infarction (AMI) was present in 31 (60.8%), diabetes mellitus (DM) in 28 (54.9%), systemic arterial hypertension in 37 (72.5%), LVD (left ventricular ejection fraction <40%) in 26 (51%), 3 vessel CAD in 31 (60.8%), and LM in 4 (7.8%). During follow-up there were 20 cardiac (39.2%) deaths, 19 (37.2%) AMI, and 3 (5.8%) patients developed congestive heart failure. There were 2 (3.9%) noncardiac deaths. Patients with DM (60.7% versus 13%; P =0.001; odds ratio [OR], 10.30; 95% confidence interval [CI], 2.46 to 43.09), LVD (76.9% versus 0%; P <0.0001; OR, 4.33; 95% CI, 2.14 to 8.74), 3-vessel CAD (51.6% versus 20%; P =0.039; OR, 4.26; 95% CI, 1.16 to 15.69), and LM (100% versus 34%; P =0.019; OR, 1.25; 95% CI, 1.004 to 1.556) were more likely to die. There was no deaths in patients with 2-vessel CAD but they had more nonfatal AMI (43.8% versus 14.3%; OR, 4.667; 95% CI, 1.188 to 18.332).

Conclusions— Patients in whom CABG could not be performed because of ENDCAD had high mortality, especially in the presence of LVD. DM (particularly insulin-dependent), LM CAD, and 3-vessel CAD were independent markers of increased risk.