Development of a median sternotomy simulation model for cardiac surgery training

Objective

We sought to develop a simulation model to train resident physicians in the performance of a median sternotomy.

Methods

A modified Delphi consensus process was used with cardiac surgery staff to develop a 20-point checklist for the safe performance of a median sternotomy. Thirteen junior cardiac surgery trainees from across Canada participated in this study to assess the simulation model. Trainees performed the sternotomy before and after reviewing an instructional video. Two senior cardiac surgery resident physicians assessed the participants with the checklist during each session. An entry and exit questionnaire was given to the participants to evaluate the simulation model.

Results

Participants scored higher after the training (14.3 ± 2.0) compared with before training (8.0 ± 3.1) (P < .001). The mean duration of time for participants to complete the sternotomy was shorter before training (188 ± 52 seconds vs 228 ± 58 seconds; P = .003). The checklist interrater reliability was κ = 0.47 (moderate) for before training and κ = 0.37 (fair) for after training. All study participants rated the simulation sessions as very useful or extremely useful.

Conclusions

Using the simulation model, training video, and checklist, trainees were able to improve their skill in performing a median sternotomy. This improvement was associated with longer times to complete all procedure steps. Rater training may further improve interrater reliability. Our median sternotomy checklist and simulation model can be adopted for the technical skills training of future cardiac surgery trainees.

Sex differences in outcomes of heart failure in an ambulatory, population-based cohort from 2009 to 2013

BACKGROUND

Heart failure remains a substantial cause of morbidity and mortality in women. We examined the sex differences in heart failure incidence, mortality and hospital admission in a population-based cohort.

METHODS

All Ontario residents who were diagnosed with heart failure in an ambulatory setting between Apr. 1, 2009, and Mar. 31, 2014, were included in this study. Incident cases of heart failure were captured through physician billing using a validated algorithm. Outcomes were mortality and hospital admission for heart failure within 1 year of the diagnosis. Probability of death and hospital admission were calculated using the Kaplan-Meier method. The hazard of death was assessed using a multivariable Cox proportional hazard model.

RESULTS

A total of 90 707 diagnoses of heart failure were made in an ambulatory setting during the study period (47% women). Women were more likely to be older and more frail, and had different comorbidities than men. The incidence of heart failure decreased during the study period in both sexes. The mortality rate decreased in both sexes, but remained higher in women than men. The female age-standardized mortality rate was 89 (95% confidence interval [CI] 80-100) per 1000 in 2009 and 85 (95% CI 75-95) in 2013, versus male age-standardized mortality rates of 88 (95% CI 80-97) in 2009 and 83 (95% CI 75-91) in 2013. Conversely, the rates of incident heart failure hospital admissions after heart failure diagnosis decreased in men and increased in women.

INTERPRETATION

Despite decreases in overall heart failure incidence and mortality in ambulatory patients, mortality rates remain higher in women than in men, and rates of hospital admission for heart failure increased in women and declined in men. Further studies should focus on sex differences in health-seeking behaviour, medical therapy and response to therapy to provide guidance for personalized care.

Developing a Strategy for the Improvement in Patient Experience in a Canadian Academic Department of Surgery

Patient experience (PE) is recognized as a key component in the quality of health-care delivery. Public reporting of hospital, division, and physician-specific PE results has added to the momentum of adopting strategies to augment this metric of care. The Ottawa Hospital embarked on a journey to improve PE as a pillar of its quality improvement plan. This article demonstrates the efforts of a single surgery department from one large urban center to improve in-hospital PE in the rapidly changing environment of medicine and surgery. A multidisciplinary group within the department and a focus group of previous surgical inpatients were organized to address immediate challenges related to inpatient PE issues. We identified concrete strategies to optimize pain control, perceptions of patient respect and dignity, perceptions of surgeon availability, discharge medication understanding, and overall experience. Also, we identified a need in our department for timely patient feedback, improved communication styles in our staff and trainees, and an internal curriculum offering additional training for our staff and residents. We anticipate that the current results would be of significant interest to other departments wishing to optimize their PE profile as part of the ongoing quality improvement process at hospitals across North America.

Native Coronary Disease Progression Post Coronary Artery Bypass Grafting

BACKGROUND

It remains unclear if graft type impacts native disease progression in the target coronary artery post coronary artery bypass grafting (CABG).

METHODS

Patients who underwent repeat angiograms at least 6 months post CABG with ≥1 arterial graft were included. Pre/post CABG angiograms were examined by 2 experienced readers. Progression was defined as new stenosis of ≥50% in a previously normal coronary, an increase in previous stenosis of ≥20%, or a new occlusion. Primary outcome was the occurrence of native disease progression in bypassed vessels. Secondary outcomes included complete occlusion, left main (LM) and distal disease progression. Cox-proportional hazard regression models were used for time-to-event outcomes.

RESULTS

Study population included 98 patients comprising 263 grafts (143 arterial/120 venous grafts). Median time from surgery to catheterization was 559 days (Interquartile Range 374,910).Ninety-one target vessels showed progression (34.6%) with 75 to complete occlusion (28.5%). Progression was not associated with graft choice (HR 0.74(0.49,1.13) p = 0.163),but was significantly associated with age(p = 0.034),previous PCI(p = 0.002),ACE inhibitor (ACEi) use(p < 0.001),CAD severity (p < 0.001),CCS class III/IV(p = 0.016) and NYHA class III/IV(p < 0.001). Progression to occlusion was significantly associated with SVG (p = 0.019), as well as previous percutaneous coronary intervention (p = 0.007) and ACEi use (p < 0.001). LM disease progression was significantly associated with peripheral vascular disease (HR 5.44(1.92, 15.46), p = 0.001), and not affected by graft type (p = 0.754).

CONCLUSIONS

Native CAD progression in non-LM coronaries is multifactorial, while SVG use was only associated with occlusion of non-LM coronaries. The implications of this study warrant consideration for increased arterial grafting in CABG patients, while the negative associations of previous PCI and ACEi use carry important clinical implications, which require further investigation.

Impact of patient characteristics on the Canadian Patient Experiences Survey-Inpatient Care: survey analysis from an academic tertiary care centre

OBJECTIVE

To determine the role of patient demographics, care domains and self-perceived health status in the analysis and interpretation of results from the Canadian Patient Experience Survey-Inpatient Care.

DESIGN

Cross-sectional survey.

SETTING

Single large Canadian two campus tertiary care academic centre.

PARTICIPANTS

Random sampling of hospital patients postdischarge.

INTERVENTION AND MAIN OUTCOME MEASURES

Logistic regression models were developed to analyse topbox scoring on four questions of global care (rate experience, recommend hospital, rate hospital, overall helped). Means of each composite domain were correlated to the four overall scores at the patient level to determine Spearman's rank correlation coefficients which were plotted against the overall (hospital) domain score for the key driver analysis.

RESULTS

Topbox scoring was decreased with worse degrees of perceived physical and mental health in all four global questions (p<0.05). Female gender and higher levels of education were associated with worse scoring on rate experience, recommend hospital and rate hospital (p<0.001). Whereas there was a significant difference between hospital departments in unadjusted measures, these differences were no longer evident after adjustment with patient covariates. Key driver analysis identified person-centred care, care transition and the domain related to emergency admission as areas of highest potential for improvement.

CONCLUSIONS

Global measures of overall care are influenced by patient-perceived physical and mental health. Caution should be exercised in using patient-satisfaction surveys to compare performance between different healthcare provision entities, as apparent differences could be explained by variation in patient mix rather than variation in performance.

Displacement of Fibrin-bound Thrombin by r-Hirudin Precludes the Use of 131l-r-Hirudin for Detecting Pulmonary Emboli in the Rabbit

Pulmonary emboli are detectable by filling defects in the pulmonary vasculature upon pulmonary angiography. Emboli derived from venous thrombi are rich in fibrin to which thrombin remains bound. Hirudin, a specific thrombin inhibitor, binds to thrombin to yield a 1:1 stoichiometric complex. We examined whether 131I-recombinant hirudin (r-hirudin) could be used to detect pulmonary emboli in rabbits. Clots were formed by re-calcifying rabbit plasma in vitro, and then injected (0.034 ml) into a femoral vein to lodge in the lungs. 131I-r-hirudin (29 ± 4 μCi/kg) was injected intravenously but emboli could not be detected by gamma camera in real time. Post-mortem analysis of lung tissue showed that 131I-r-hirudin did not associate with emboli prepared with 125I-fibrin. Because of these findings, we used different techniques to look at the binding of hirudin to plasma clots. Clots formed in vitro were incubated with 131I-r-hirudin in the presence of equimolar amounts of 125I-albumin; specific binding of 131I-r-hirudin was not observed. Experiments with immobilized fibrin(ogen) showed that 125I-r-hirudin did not bind to and remain with fibrin-bound 131I-thrombin but did lead to the inactivation and displacement of up to 70% of bound thrombin as r-hirudin-thrombin complex; residual thrombin bound to fibrin remained active. Thus, released r-hirudin-thrombin complex is probably cleared rapidly from the region of the embolus in vivo; radioiodinated r-hirudin may not, therefore, be useful as a marker for detecting emboli.

Platelet Accumulation on Fibrin-coated Polyethylene: Role of Platelet Activation and Factor XIII

Platelet accumulation on small- and medium-calibre vascular grafts plays a significant role in graft occlusion. We examined platelet accumulation on the surface of fibrin-coated polyethylene tubing (internal diameter 0.17 cm) during 10 min of flow (l0ml/min) at high wall shear rate (764 s-1). Washed platelets labelled with 51Cr were resuspended in Tyrode solution containing albumin, apyrase and red blood cells (hematocrit 40%). When the thrombin that was used to form the fibrin-coated surface was inactivated with FPRCH2C1 before perfusion of the tubes with the platelet:red blood cell suspension, the accumulation of platelets was 59,840 ± 27,960 platelets per mm2, whereas accumulation on fibrin with residual active thrombin was 316,750 ± 32,560 platelets per mm2 (n = 4). When the fibrin on the surface was cross-linked by including recombinant factor XIII (rFXIII) in the fibrinogen solution used to prepare the fibrin-coated surface, platelet accumulation, after thrombin neutralization, was reduced by the cross-linking from 46,974 ± 9702 to 36,818 ± 7964 platelets per mm2 (n = 12, p <0.01). Platelet accumulation on tubes coated with D-dimer was ten times less than on tubes coated with D-domain; this finding also supports the observation that cross-linking of fibrin with the formation of γ-γ dimers reduces platelet accumulation on the fibrin-coated surface. Thrombin-activated platelets themselves were shown to cross-link fibrin when they had adhered to it during perfusion, or in a static system in which thrombin was used to form clots from FXIII-free fibrinogen in the presence of platelets. Thus, cross-linking of fibrin by FXIII in plasma or from platelets probably decreases the reactivity of the fibrin-containing thrombi to platelets by altering the lysine residue at or near the platelet-binding site of each of the γ-chains of the fibrinogen which was converted into the fibrin of these thrombi.

The Effect of Antithrombin III-Independent Thrombin Inhibitors and Heparin on Fibrin Accretion onto Fibrin-Coated Polyethylene

Prosthetic vascular grafts become coated with a layer of fibrin that contributes to graft thrombosis and occlusion. We compared the effect of antithrombin III-independent inhibitors of thrombin with heparin for their ability to prevent fibrin accretion onto a model of a vascular graft formed in vitro by coating polyethylene tubing with thrombin bound to a layer of polymerized fibrin. Equivalent antithrombin concentrations of heparin, D-Phe-Pro-Arg CH2Cl (PPACK), recombinant hirudin (r-hirudin), and Hirulog-1 were added to barium chloride-adsorbed plasma containing radiolabelled fibrinogen. Whereas, PPACK and r-hirudin persistently inhibited fibrin accretion, the inhibition by heparin was transient. Hirulog-1 had no effect on early fibrin accretion and was actually associated with enhanced accretion at 30 min (control 11.7 ± 2.0 μg fibrin/cm2; Hirulog-1, 18.4 ± 3.5 μg fibrin/cm2, p <0.001). Both Hirulog-1 and r-hirudin displaced radiolabelled thrombin from the fibrin surface. Whereas hirudin-thrombin complexes are stable, Hirulog-1 produces only transient inhibition of the displaced thrombin thereby accounting for the enhanced fibrin accretion with this anticoagulant. These studies show that the antithrombin III-independent inhibitors, r-hirudin and PPACK, are more effective inhibitors of fibrin accretion onto fibrin-coated polyethylene than heparin or Hirulog-1. In addition, they emphasize the importance of determining the ability of anticoagulants to displace thrombin from fibrin and to form stable thrombin-inhibitor complexes; lack of stability of thrombin-inhibitor complexes must be countered by levels of anticoagulant that are adequate to maintain its effectiveness.