Experiences of patients enrolled and staff involved in the prehabilitation of elective patients undergoing cardiac surgery trial: a nested qualitative study.

The purpose of this study was to understand the views and experiences of patients enrolled and staff involved in the prehabilitation of elective patients undergoing cardiac surgery trial. This sub-study was informed by normalisation process theory, a framework for evaluating complex interventions, and used consecutive sampling to recruit patients assigned to both the intervention and control groups. Patients and all staff involved in delivering the trial were invited to participate in focus groups, which were recorded, transcribed verbatim and subjected to reflexive thematic analysis. Five focus groups were held comprising 24 participants in total (nine patients assigned to the prehabilitation; seven assigned to control; and eight staff). Five themes were identified. First, preparedness for surgery reduced fear, where participants described that knowing what to expect from surgery and preparing the body physically increased feelings of control and subsequently reduced apprehension regarding surgery. Second, staff were concerned but trusted in a safe environment, describing how, despite staff's concerns regarding the risks of exercise in this population, the patients felt safe in their care whilst participating in an exercise programme in hospital. Third, rushing for recovery and the curious carer, where patients from both groups wanted to mobilise quickly postoperatively whilst staff visited patients on the ward to observe their recovery progress. Fourth, to survive and thrive postoperatively, reflecting staff and patients' expectations from the trial and what motivated them to participate. Fifth, benefits are diluted by lengthy waiting periods, reflecting the frustration felt by patients waiting for their surgery after completing the intervention and the fear about continuing exercise at home before they had been 'fixed'. To conclude, functional exercise capacity may not have improved following prehabilitation in people before elective cardiac surgery due to concerns regarding the safety of exercise that may have hindered delivery and receipt of the intervention. Instead, numerous non-physical benefits were elicited. The information from this qualitative study offers valuable recommendations regarding refining a prehabilitation intervention and conducting a subsequent trial.

A randomised controlled trial of prehabilitation in patients undergoing elective cardiac surgery.

The feasibility, safety and efficacy of prehabilitation in adult patients awaiting elective cardiac surgery are unknown. A total of 180 participants undergoing elective cardiac surgery were allocated randomly to receive either standard pre-operative care or prehabilitation, consisting of pre-operative exercise and inspiratory muscle training. The primary outcome was change in six-minute walk test distance from baseline to pre-operative assessment. Secondary outcomes included change in inspiratory muscle strength (maximal inspiratory pressure); sarcopenia (handgrip strength); quality of life and compliance. Safety outcomes were pre-specified surgical and pulmonary complications and adverse events. All outcomes were assessed at baseline; at pre-operative assessment; and 6 and 12 weeks following surgery. Mean (SD) age was 64.7 (10.2) years; 33/180 (18%) were women. In total, 65/91 (71.4%) participants who were allocated to prehabilitation attended at least four of eight supervised in-hospital exercise classes; participants aged > 50 years were more likely than younger participants to attend (odds ratio (95%CI) of 4.6 (1.0-25.1)). Six-minute walk test was not significantly different between groups (mean difference (95%CI) -7.8 m (-30.6-15.0), p = 0.503) in the intention-to-treat analysis. Subgroup analyses based on tests for interaction indicated improvements in six-minute walk test distance were larger amongst sarcopenic patients in the prehabilitation group (p = 0.004). Change in maximal inspiratory pressure from baseline to all time-points was significantly greater in the prehabilitation group, with the greatest mean difference (95%CI) observed 12 weeks after surgery (10.6 cmH2 O (4.6-16.6) cmH2 O, p < 0.001). There were no differences in handgrip strength or quality of life up to 12 weeks after surgery. There was no significant difference in postoperative mortality (one death in each group), surgical or pulmonary complications. Of 71 pre-operative adverse events, six (8.5%) were related to prehabilitation. The combination of exercise and inspiratory muscle training in a prehabilitation intervention before cardiac surgery was not superior to standard care in improving functional exercise capacity measured by six-minute walk test distance pre-operatively. Future trials should target patients living with sarcopenia and include inspiratory muscle strength training.

Multi-channel SPR biosensor based on PCF for multi-analyte sensing applications.

This paper presents a theoretical investigation of a novel holey fiber (Photonic Crystal Fiber (PCF)) multi-channel biosensor based on surface plasmon resonance (SPR). The large gold coated micro fluidic channels and elliptical air hole design of our proposed biosensor aided by a high refractive index over layer in two channels enables operation in two modes; multi analyte sensing and self-referencing mode. Loss spectra, dispersion and detection capability of our proposed biosensor for the two fundamental modes (HE(11)(x) and HE(11)(y)) have been elucidated using a Finite Element Method (FEM) and Perfectly Matching Layers (PML).

Dual channel planar waveguide surface plasmon resonance biosensor for an aqueous environment.

A theoretical study on a dual channel planar waveguide surface plasmon biosensor is presented in this paper. The proposed device consists of a planar waveguide with two active regions. It has been demonstrated that the proposed waveguide sensor can be configured to operate in either multi analyte or self referencing mode. The channel discriminative property of the device is investigated using an eigenmode solver with perfectly matched layers (PML).

Design and optimization of a novel surface plasmon resonance biosensor based on Otto configuration.

A theoretical study on a novel planar waveguide surface Plasmon Biosensor is presented in this paper. The proposed biosensor has a configuration similar to the Otto excitation mechanism for surface Plasmon polaritons. The performance of the device with respect to key system parameters such as gap-width and device length is investigated using an eigenmode solver with perfectly matched layers (PML). Device resolution of 2.3 x 10(-6) RIU has been demonstrated for an aqueous analyte.

Ultrasound-mediated delivery of TIMP-3 plasmid DNA into saphenous vein leads to increased lumen size in a porcine interposition graft model.

Progressive saphenous vein graft (SVG) narrowing and occlusion remains a major limitation of coronary artery bypass grafting and is an important target for gene therapy. Ex vivo adenoviral gene transfer of tissue inhibitor of metalloproteinase 3 (TIMP-3) reduces adverse SVG remodelling postarterialization, but concerns remain over the use of viral vectors in patients. Ultrasound exposure (USE) in the presence of echocontrast microbubbles (ECM) substantially enhances nonviral gene delivery. We investigated the effects of ultrasound-enhanced gene delivery (UEGD) of TIMP-3 plasmid on vascular remodelling in porcine SVG. Maximal luciferase activity (3000-fold versus naked plasmid alone) and TIMP-3 transgene expression in porcine vascular smooth muscle cells in vitro was achieved using USE at 1 MHz, 1.8 mechanical index (MI), 6% duty cycle (DC) in the presence of 50% (v/v) BR14 ECM (Bracco). These conditions were therefore utilized for subsequent studies in vivo. Yorkshire White pigs received carotid interposition SVG that were untransfected or had undergone ex vivo UEGD of lacZ (control) or TIMP-3 plasmids. At 28 d postgrafting, lumen and total vessel area were significantly greater in the TIMP-3 group (10.1+/-1.2 and 25.5+/-2.2 mm2, respectively) compared to untransfected (6.34+/-0.5 and 20.8+/-1.9 mm2) or lacZ-transfected (6.1+/-0.7 and 19.7+/-1.2 mm2) controls (P<0.01). These data indicate that nonviral TIMP-3 plasmid delivery by USE achieves significant biological effects in a clinically relevant model of SV grafting, and is the first study to demonstrate the potential for therapeutic UEGD to prevent SVG failure.

Prosthetic valve endocarditis: early and late outcome following medical or surgical treatment.

OBJECTIVE: To compare the early and late outcome of medical and surgical treatment in patients with prosthetic valve endocarditis within a single unit. DESIGN: All patients with proven prosthetic valve endocarditis treated in one institution between 1989 and 1999 were studied. RESULTS: There were 66 patients (24 female, 42 male), mean (SD) age 57 (14) years. Of these, 28 were treated with antibiotics alone and 38 with a combination of antibiotics and surgery. The in-hospital mortality for the antibiotic group was 46% and for the surgical group, 24%. However, seven patients in the antibiotic group were considered too sick for curative treatment. The mortality in the remaining 21 medically treated patients (6/21; 29%) was not significantly different from that in the surgically treated patients (p = 0.15). Six patients in the medically treated group and one in the surgically treated group required late reoperation. Endocarditis recurred in three patients in the medically treated group, two of whom were treated surgically, and in one patient in the surgically treated group. Kaplan-Meier survival at 10 years was 28% in the medically treated group v 58% in the surgically treated group (p = 0.04). Freedom from endocarditis at five years was 60% in the surgically treated group and 65% in the medically treated group. CONCLUSIONS: Prosthetic valve endocarditis is a serious condition with high early and late mortality, irrespective of the treatment employed. These data show that selected patients with prosthetic valve endocarditis can be successfully treated with antibiotics alone. If required, surgery in this difficult group of patients can provide satisfactory freedom from recurrent infection.

Coronary artery aneurysm with a fistulous connection to the right atrium mimicking a sinus of Valsalva aneurysm.

Coronary artery aneurysms are uncommon and may be complicated by rupture, thromboembolic phenomenon, and more rarely fistulation into one of the cardiac chambers. This case report highlights the difficulty in making a preoperative diagnosis of a coronary artery aneurysm that has fistulated into the right atrium, and lists possible differential diagnoses.

Aorto-right atrial fistula associated with native tricuspid valve endocarditis.

Abnormal connections between the ascending aorta and the cardiac chambers are rare. Most are due to ruptured aneurysms of the sinus of Valsalva. Congenital fistulae between the aorta and left atrium are described. We report a case of native tricuspid valve endocarditis associated with a fistula between the right atrium and the aorta.

Evaluation of the dopamine response to stress in man.

Because the role of circulating dopamine (DA) in the sympathetic nervous system response to stress remains unclear, alterations in peripheral DA concentrations were determined in healthy volunteers after assuming upright posture (n = 6), hand immersion in ice water (cold pressor, n = 6), and insulin-induced hypoglycemia (n = 11) and in 17 comatose patients with severe brain injury (11 head trauma and 6 intracranial hemorrhage). Changes in DA levels were compared to increases in epinephrine (E) and norepinephrine (NE), all of which were measured by the radioenzymatic technique. The minimum sensitivities were 42, 22, and 38 pg/ml, respectively. In 19 normal men and 22 women, basal DA levels were below assay sensitivity in 31 and were 85 +/- 7 (+/- SE) pg/ml in the remainder. Plasma E was measurable in all but 7 subjects, with a mean concentration of 41 +/- 4 pg/ml. NE levels were 201 +/- 17 pg/ml in 30 of the 31 subjects in whom it was detectable. There was no sex difference for any of the catecholamines. Upon standing, neither DA nor E changed significantly, but NE, increased by 176 +/- 40 pg/ml (P less than 0.0025). There were no significant changes in DA or E concentrations during the cold pressor test, while NE increased by 212 +/- 66 pg/ml (P less than 0.025). Compared to the E (1044 +/- 356 pg/ml; P less than 0.02) and NE (233 +/- 62 pg/ml; P less than 0.005) increments after hypoglycemia, the maximal DA increment, although significant (62 +/- 22 pg/ml; P less than 0.025), was less than those of the other catecholamines. DA levels were measurable in only 7 of 40 samples from 17 brain-injured patients and was 72 +/- 13 pg/ml in the remainder. However, E and NE levels were detectable in 79% of the samples and were significantly greater than normal (125.6 +/- 14 and 594 +/- 59 pg/ml; P less than 0.001, respectively). It is concluded that basal DA levels are generally below the assay limits of detectability. Furthermore, measurement of circulating levels suggests that DA participates in the general sympathetic response only when the adrenal component is maximally activated.