Serum neurofilament light chain in functionally relevant coronary artery disease and adverse cardiovascular outcomes

Background: Functionally relevant coronary artery disease (fCAD), causing symptoms of myocardial ischemia, can currently only be reliably detected with advanced cardiac imaging. Serum neurofilament light chain (sNfL) is a biomarker for neuro-axonal injury known to be elevated by cardiovascular (CV) risk factors and cerebrovascular small-vessel diseases. Due to their pathophysiological similarities with fCAD and the link to CV risk factors, we hypothesised that sNfL may have diagnostic and prognostic value for fCAD and adverse cardiovascular outcomes.Methods: Of the large prospective Basel VIII study (NCT01838148), 4'016 consecutive patients undergoing cardiac work-up for suspected fCAD were included (median age 68 years, 32.5% women, 46.9% with history of CAD). The presence of fCAD was adjudicated using myocardial perfusion imaging single-photon emission tomography (MPI-SPECT) and coronary angiography. sNfL was measured using a high-sensitive single-molecule array assay. All-cause and cardiovascular death, myocardial infarction (MI), and stroke/transient ischaemic attack (TIA) during 5-year follow-up were the prognostic endpoints.Results: The diagnostic accuracy of sNfL for fCAD as quantified by the area under the curve (AUC) was low (0.58, 95%CI 0.56-0.60). sNfL was strongly associated with age, renal dysfunction, and body mass index and was a strong and independent predictor of all-cause death, cardiovascular death, and stroke/TIA but not MI. Time-dependent AUC for cardiovascular-death at 1-year was 0.85, 95%CI 0.80-0.89, and 0.81, 95%CI 0.77-0.86 at 2-years.Conclusion: While sNfL concentrations did not show a diagnostic role for fCAD, in contrast, sNfL was a strong and independent predictor of cardiovascular outcomes, including all-cause death, cardiovascular death and stroke/TIA.

Pulmonary transit time of cardiovascular magnetic resonance perfusion scans for quantification of cardiopulmonary haemodynamics

AIMS

Pulmonary transit time (PTT) is the time blood takes to pass from the right ventricle to the left ventricle via pulmonary circulation. We aimed to quantify PTT in routine cardiovascular magnetic resonance imaging perfusion sequences. PTT may help in the diagnostic assessment and characterization of patients with unclear dyspnoea or heart failure (HF).

METHODS AND RESULTS

We evaluated routine stress perfusion cardiovascular magnetic resonance scans in 352 patients, including an assessment of PTT. Eighty-six of these patients also had simultaneous quantification of N-terminal pro-brain natriuretic peptide (NTproBNP). NT-proBNP is an established blood biomarker for quantifying ventricular filling pressure in patients with presumed HF. Manually assessed PTT demonstrated low inter-rater variability with a correlation between raters >0.98. PTT was obtained automatically and correctly in 266 patients using artificial intelligence. The median PTT of 182 patients with both left and right ventricular ejection fraction >50% amounted to 6.8 s (Pulmonary transit time: 5.9-7.9 s). PTT was significantly higher in patients with reduced left ventricular ejection fraction (<40%; P < 0.001) and right ventricular ejection fraction (<40%; P < 0.0001). The area under the receiver operating characteristics curve (AUC) of PTT for exclusion of HF (NT-proBNP <125 ng/L) was 0.73 (P < 0.001) with a specificity of 77% and sensitivity of 70%. The AUC of PTT for the inclusion of HF (NT-proBNP >600 ng/L) was 0.70 (P < 0.001) with a specificity of 78% and sensitivity of 61%.

CONCLUSION

PTT as an easily, even automatically obtainable and robust non-invasive biomarker of haemodynamics might help in the evaluation of patients with dyspnoea and HF.

Using high-sensitivity cardiac troponin for the exclusion of inducible myocardial ischemia in patients without previously known coronary artery disease

Background

The rapid and safe exclusion of functionally relevant coronary artery disease (CAD) is a crucial, yet unmet clinical need. High-sensitivity cardiac troponin (hs-cTn) may be an attractive strategy, particularly in patients without previously known CAD.

Purpose

To derive and internally validate optimal rule-out cutoffs for an early and safe exclusion of functionally relevant CAD in symptomatic patients without previously known CAD.

Methods

In an ongoing single-center, prospective, cohort study, we enrolled consecutive patients without previously known CAD that were referred with symptoms possibly related to functionally relevant CAD. Cardiac troponin concentrations were measured at presentation using two high-sensitivity assays (Elecsys hs-cTnT and Architect hs-cTnI). Presence of functionally relevant CAD was adjudicated by 2 independent cardiologists, blinded to hs-cTn measurements, using MPI-SPECT/CT in all patients, as well as coronary angiography and fractional flow reserve measurements, whenever available. The primary diagnostic outcome was safety for early rule-out of functionally relevant CAD, quantified by sensitivity and the negative predictive value (NPV). The co-primary prognostic outcomes were cumulative incidences of cardiovascular death and all-cause death after 5 years. A NPV ≥90% and sensitivity ≥90% were predefined as acceptable performance criteria. The derived cutoffs were further evaluated in pre-specified subgroups. Internal validity was assessed with a bootstrapping procedure for a realistic estimate in similar future patients. Cumulative incidence curves stratified by the presence of functionally relevant CAD and hs-cTn concentrations below and above the derived cutoffs were constructed.

Results

Among 2111 eligible patients, 498 (23.6%) had a final diagnosis of functionally relevant CAD. Median age was 68 years and 938 (44.4%) were female. For ruling out functionally relevant CAD, a hs-cTnT concentration &lt;5 ng/L resulted in a sensitivity of 90.8% (95% CI: 87.9–93.0%) and a NPV of 90.2% (95% CI: 87.1–92.5), triaging 468 (22.2%) patients towards rule-out. Similarly, a hs-cTnI concentration &lt;2 ng/L resulted in a sensitivity of 91.6% (95% CI: 88.8–93.7%) and a NPV of 90.0% (95% CI: 86.8–92.6), triaging 422 (20.0%) patients. Internal validation showed robustness of these findings. The diagnostic performance of the derived cutoffs did not significantly vary across the subgroups. Hs-cTn concentrations above the derived cutoffs were associated with a substantially higher cumulative event rate of cardiovascular death (hs-cTnT: 7.0% vs. 0.8%; hs-cTnI: 6.6% vs. 1.2%) and all-cause death (hs-cTnT: 14.3% vs. 2.4%; hs-cTnI: 13.1% vs. 4.4%) during 5-years follow-up (log rank p&lt;0.001 for all).

Conclusion

In symptomatic patients without previously known CAD, very low hs-cTn concentrations may generally allow to safely and effectively exclude functionally relevant CAD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss National Science FoundationSwiss Heart Foundation

Associations between fully-automated, 3D-based functional analysis of the left atrium and classification schemes in atrial fibrillation

Background

Atrial fibrillation (AF) has been linked to left atrial (LA) enlargement. Whereas most studies focused on 2D-based estimation of static LA volume (LAV), we used a fully-automatic convolutional neural network (CNN) for time-resolved (CINE) volumetry of the whole LA on cardiac MRI (cMRI). Aim was to investigate associations between functional parameters from fully-automated, 3D-based analysis of the LA and current classification schemes in AF.

Methods

We retrospectively analyzed consecutive AF patients who underwent cMRI on 1.5T systems including a stack of oblique-axial CINE series covering the whole LA. The LA was automatically segmented by a validated CNN. In the resulting volume-time curves, maximum, minimum and LAV before atrial contraction were automatically identified. Active, passive and total LA emptying fractions (LAEF) were calculated and compared to clinical classifications (AF Burden score (AFBS), increased stroke risk (CHA₂DS₂VASc≥2), AF type (paroxysmal/persistent), EHRA score, and AF risk factors). Moreover, multivariable linear regression models (mLRM) were used to identify associations with AF risk factors.

Results

Overall, 102 patients (age 61±9 years, 17% female) were analyzed. Active LAEF (LAEF_active) decreased significantly with an increase of AFBS (minimal: 44.0%, mild: 36.2%, moderate: 31.7%, severe: 20.8%, p<0.003) which was primarily caused by an increase of minimum LAV. Likewise, LAEF_active was lower in patients with increased stroke risk (30.7% vs. 38.9%, p = 0.002). AF type and EHRA score did not show significant differences between groups. In mLRM, a decrease of LAEF_active was associated with higher age (per year: -0.3%, p = 0.02), higher AFBS (per category: -4.2%, p<0.03) and heart failure (-12.1%, p<0.04).

Conclusions

Fully-automatic morphometry of the whole LA derived from cMRI showed significant relationships between LAEF_active with increased stroke risk and severity of AFBS. Furthermore, higher age, higher AFBS and presence of heart failure were independent predictors of reduced LAEF_active, indicating its potential usefulness as an imaging biomarker.

Soluble urokinase plasminogen activator receptor and functionally relevant coronary artery disease: a prospective cohort study

BACKGROUND

Soluble urokinase plasminogen activator receptor (suPAR) is an emerging biomarker associated with anatomical CAD burden and cardiovascular outcomes including myocardial infarction (MI) and death. We aimed at validating previous findings of the prognostic value of suPAR and evaluated its diagnostic potential for functional relevant CAD (fCAD).

METHODS

Consecutive patients with suspected fCAD were enrolled. Adjudication of fCAD was performed blinded to suPAR concentrations by myocardial perfusion single photon emission tomography (MPI-SPECT) and coronary angiography. Prognostic outcome measures included all-cause, cardiovascular death, and incident MI during 2-year follow-up.

RESULTS

Among consecutive 968 patients, SuPAR concentrations were higher in patients with fCAD compared to those without (3.45ng/mL versus 3.20ng/mL, p = 0.007), without acceptable diagnostic accuracy (area under the curve [AUC]: 0.56, 95%CI 0.52-0.60). SuPAR correlated with high-sensitivity cardiac-troponin (hs-cTn) T (Spearman's rho (ρ) 0.393, p < 0.001), NT-proBNP (ρ = 0.327, p < 0.001), age (ρ = 0.364, p < 0.001) and very weakly with coronary atherosclerosis (ρ = 0.123, p < 0.001). Prognostic discrimination of suPAR was moderate for cardiovascular death (AUC =0.72, 95%CI 0.62-0.81) and all-cause death (AUC =0.72, 95%CI 0.65-0.79) at 2-years. SuPAR remained a significant predictor for all-cause death in the full model (HR =1.96, p = 0.001).

CONCLUSIONS

SuPAR was an independent predictor of all-cause death, without diagnostic utility for fCAD.

Gut microbiota-dependent metabolite trimethylamine N-oxide (TMAO) and cardiovascular risk in patients with suspected functionally relevant coronary artery disease (fCAD)

BACKGROUND

Trimethylamine N-oxide (TMAO) has been associated with cardiovascular outcomes. However, the diagnostic value of TMAO and its precursors have not been assessed for functionally relevant coronary artery disease (fCAD) and its prognostic potential in this setting needs to be evaluated.

METHODS

Among 1726 patients with suspected fCAD serum TMAO, and its precursors betaine, choline and carnitine, were quantified using liquid chromatography tandem mass spectrometry. Diagnosis of fCAD was performed by myocardial perfusion single photon emission tomography (MPI-SPECT) and coronary angiography blinded to marker concentrations. Incident all-cause death, cardiovascular death (CVD) and myocardial infarction (MI) were assessed during 5-years follow-up.

RESULTS

Concentrations of TMAO, betaine, choline and carnitine were significantly higher in patients with fCAD versus those without (TMAO 5.33 μM vs 4.66 μM, p < 0.001); however, diagnostic accuracy was low (TMAO area under the receiver operating curve [AUC]: 0.56, 95% CI [0.53-0.59], p < 0.001). In prognostic analyses, TMAO, choline and carnitine above the median were associated with significantly (p < 0.001 for all) higher cumulative events for death and CVD during 5-years follow-up. TMAO remained a significant predictor for death and CVD even in full models adjusted for renal function (HR = 1.58 (1.16, 2.14), p = 0.003; HR = 1.66 [1.07, 2.59], p = 0.025). Prognostic discriminative accuracy for TMAO was good and robust for death and CVD (2-years AUC for CVD 0.73, 95% CI [0.65-0.80]).

CONCLUSION

TMAO and its precursors, betaine, choline and carnitine were significantly associated with fCAD, but with limited diagnostic value. TMAO was a strong predictor for incident death and CVD in patients with suspected fCAD.

CLINICAL TRIAL REGISTRATION

NCT01838148.

Management and outcomes of patients on maintenance dialysis during the first and second wave of the COVID-19 pandemic in Geneva, Switzerland

BACKGROUND

Patients on maintenance dialysis are at high risk for serious complications from COVID-19 infection, including death. We present an overview of local experience with dialysis unit management and reorganisation, local epidemiology and outcomes during the COVID-19 outbreak in Geneva, Switzerland, where SARS-CoV-2 incidence was one of the highest in Europe.

METHODS

All SARS-CoV-2-positive outpatients on maintenance dialysis were transferred from their usual dialysis facility to the Geneva University Hospitals dialysis unit to avoid creation of new clusters of transmission. Within this unit, appropriate mitigation measures were enforced, as suggested by the institutional team for prevention and control of infectious diseases.

RESULTS

From 25 February to 31 December 2020, 82 of 279 patients on maintenance dialysis tested positive for SARS-CoV-2 during two distinct waves, with an incidence rate of 73 cases per 100,000 person-days during the first wave and 342 cases per 100,000 during the second wave, approximately four- to six-fold higher than the general population. The majority of infections (55%) during both waves were traced to clusters. Most infections (62%) occurred in men. Sixteen patients (34%) died from COVID-19 related complications. Deceased patients were older and had a lower body mass index as compared with patients who survived the infection.

CONCLUSION

SARS-CoV-2 is associated with high infection and fatality rates in the dialysis population. Strict mitigation measures seemed to be effective in controlling infection spread among patients on maintenance dialysis outside of clusters. Large scale epidemiological studies are needed to assess the efficacy of preventive measures in decreasing infection and mortality rates within the dialysis population.

Is faster better? Impact of operative time on postoperative outcomes after VATS anatomical pulmonary resection

Objective

Video-Assisted Thoracic Surgery (VATS) is now the preferred approach for standard anatomical pulmonary resections. However, operative time (OT) for this technique is correlated to many aspects, such as the surgical complexity or the surgeon’s experience and skills. The aim of this study was to identify the factors associated with prolonged OTs and to assess the impact of OT on the development of post-operative complications after VATS anatomical pulmonary resections.

Methods

Retrospective monocentric study including all consecutive patients undergoing a VATS anatomical pulmonary resection for benign or malignant lesions between January 2010 and December 2019. Postoperative outcomes were compared between short (&lt;150 minutes) and long (≥150 minutes) OTs. A multivariate analysis was carried out to identify predictors of longer OTs and post-operative complications.

Results

A total of 836 patients underwent a VATS anatomical pulmonary resection for malignant (n = 767, 91.7%) or benign (n = 69, 8.3%) lesions. Lobectomies were performed in 555 (66.4%), segmentectomies in 250 (29.9%), sleeve lobectomies in 16 (1.9%), bilobectomies in 11 (1.3%) and pneumonectomy in 4 (0.5%) patients. The conversion rate to thoracotomy was 7.7%. Of those 836 patients, 495 (59.2%) were operated within 150 minutes. During the 30-postoperative day period, the overall morbidity was significantly lower in the short OT group (29.1% vs. 40.5%; p = 0.001). Both the duration of drainage (3 vs. 4 days; p &lt; 0.00001) and the length of hospital stay (6 vs. 7 days; p &lt; 0.00001) were significantly reduced in the short OT group. Two predictors of long OT were identified on multivariate analysis: male sex (OR 1.41, p = 0.04) and neoadjuvant chemotherapy (OR 3.46, p = 0.003). A long OT was identified as an individual predictor of postoperative complications (OR 1.84, p &lt; 0.0001).

Conclusion

A prolonged OT is an individual risk factor for postoperative complications in patients undergoing VATS anatomical pulmonary resection.

Cryoballoon Ablation of Atrial Fibrillation Without Demonstration of Pulmonary Vein Occlusion-The Simplify Cryo Study

Background: The demonstration of pulmonary vein (PV) occlusion is routinely performed and considered a prerequisite for successful cryoballoon (CB) ablation of atrial fibrillation (AF). The purpose of this study was to assess the feasibility and impact on procedural parameters and outcome of a standardized procedural protocol without demonstrating PV occlusion.

Methods and Results: Consecutive patients undergoing CB pulmonary vein isolation (PVI) were studied. After cMRI assessment, patients treated by PVI using a novel no-contrast (NC) protocol without routine contrast injections to demonstrate PV occlusion (NC group) were compared to patients undergoing PVI with contrast injections to demonstrate PV occlusion (standard group). One hundred patients with paroxysmal or persistent AF (age 61 ± 10 years, ejection fraction 59 ± 11%, left atrial volume index 37.2 ± 2.0 mL/m²) were studied. The NC protocol was feasible in 72 of 75 patients (96%). Total procedure time and fluoroscopy time were 64.0 ± 14.1 min and 11.0 ± 4.6 min in the NC group and 92.0 ± 25.3 min and 18.0 ± 6.0 min in the standard group, respectively (all p < 0.001). Dose area product was 368 ± 362 cGy^*cm² in the NC group compared to 1928 ± 1541 cGy^*cm² in the standard group (p < 0.001). Forty-five of 75 patients (60%) in the NC group and 16 of 25 patients (64%) in the standard group remained in stable sinus rhythm after a single PVI and a 1-year follow-up (p = 0.815).

Conclusions: Performing CB ablation without using contrast injections to demonstrate PV occlusion was feasible, resulted in reduced radiation exposure, and increased the efficiency of the procedure.

Nichtrauchen ist clever: a smoking prevention program for schoolchildren and what we learn from the kids

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): PFIZER: unrestricted medical grant

Background

Tobacco consumption is an important preventable cause of premature death worldwide. Nevertheless, smoking is still common, globally. Smoking in adulthood is closely associated with smoking during adolescence. Therefore, as a global epidemic, tobacco consumption must not only be tackled in adults, but it is particularly important to focus on smoking prevention among young people.

Purpose

In 2014, a hospital-based smoking prevention program "Nichtrauchen ist clever!" (NIC!) for adolescents was initiated, consisting of three parts: namely a workshop, a film, and a patient interview. The aim of the study was to evaluate the acceptance of the program, and to explore participants’ awareness on smoking related diseases and factors that promote smoking initiation.

Methods

We performed an observational study to evaluate students’ acceptance of the program and their smoking habits, and a qualitative approach, to assess their view on reasons for smoking initiation and their knowledge about smoking-related diseases.

Results

Between January 2016 and December 2019, 1658 students participated our observational study with a mean age of 13.3 years (SD ±0.9). Twenty-six percent (429/1658) have already tried tobacco products (so called triers), specifically cigarettes, electronic (e)-cigarettes, and shisha. Use of e-cigarettes was most popular among triers 58% (252/429). All parts of the program were widely rated as good and excellent, and 88% (1408/1604) of participants reported they had acquired good or excellent knowledge about smoking.

Particularly lung cancer, cancer in general and heart diseases were frequently mentioned to be smoking related; peer pressure, stress and coolness were identified as reasons for smoking initiation. The influence of marketing and multimedia on smoking behaviour in the young was barely noticed.

Conclusion

NIC!" had a high acceptance among the participants and a large number of students reported relevant knowledge gain. We identified important knowledge-gaps relating smoking initiation and smoking related diseases, helping to improve further smoking prevention approaches.

Endothelial dysfunction is not a predictor of outcome in chronic obstructive pulmonary disease

Background

Local airway inflammation may cause systemic changes which result in endothelial dysfunction. Only a few studies have used reactive hyperemia peripheral arterial tonometry (RH-PAT) in patients with chronic obstructive pulmonary disease (COPD) in order to measure their endothelial dysfunction.

Objective

To determine the efficacy of endothelial dysfunction, measured by RH-PAT, in assessing disease severity and systemic burden in a cohort of COPD patients.

Methods

In this prospective, monocentric study, 157 patients with moderate to very severe COPD (GOLD class II-IV) were examined for endothelial dysfunction using RH-PAT (Itamar medical Ltd., Caesarea, Israel). In a nested-cohort, examination was repeated at exacerbation. The association between reactive hyperemia index (RHI), augmentation index (AI) and disease severity and outcome parameters was analysed.

Results

57% of the COPD patients had a dysfunctional endothelium and the median (IQR) RHI was 1.42 (1.27–1.53). Exacerbation of COPD was not associated with a significant change in RHI (p = 0.625) or ΑΙ (p = 0.530). None of the diagnostic or clinical outcomes of COPD was associated with RHI or arterial stiffness.

Conclusion

Endothelial dysfunction is common in COPD. However, it does not seem to be a predictor neither of disease severity, nor of outcome and does not change during exacerbations of the disease.

Using High-Sensitivity Cardiac Troponin for the Exclusion of Inducible Myocardial Ischemia in Symptomatic Patients: A Cohort Study

BACKGROUND

The optimal noninvasive method for surveillance in symptomatic patients with stable coronary artery disease (CAD) is unknown.

OBJECTIVE

To apply a novel approach using very low concentrations of high-sensitivity cardiac troponin I (hs-cTnI) for exclusion of inducible myocardial ischemia in symptomatic patients with CAD.

DESIGN

Prospective diagnostic cohort study. (ClinicalTrials.gov: NCT01838148).

SETTING

University hospital.

PATIENTS

1896 consecutive patients with CAD referred with symptoms possibly related to inducible myocardial ischemia.

MEASUREMENTS

Presence of inducible myocardial ischemia was adjudicated using myocardial perfusion imaging with single-photon emission computed tomography, as well as coronary angiography and fractional flow reserve measurements where available. Staff blinded to adjudication measured circulating hs-cTn concentrations. An hs-cTnI cutoff of 2.5 ng/L, derived previously in mostly asymptomatic patients with CAD, was assessed. Predefined target performance criteria were at least 90% negative predictive value (NPV) and at least 90% sensitivity for exclusion of inducible myocardial ischemia. Sensitivity analyses were based on measurements with an hs-cTnT assay and an alternative hs-cTnI assay with even higher analytic sensitivity (limit of detection, 0.1 ng/L).

RESULTS

Overall, 865 patients (46%) had inducible myocardial ischemia. The hs-cTnI cutoff of 2.5 ng/L provided an NPV of 70% (95% CI, 64% to 75%) and a sensitivity of 90% (CI, 88% to 92%) for exclusion of inducible myocardial ischemia. No hs-cTnI cutoff reached both performance characteristics predefined as targets. Similarly, using the alternative assays for hs-cTnI or hs-cTnT, no cutoff achieved the target performance: hs-cTnT concentrations less than 5 ng/L yielded an NPV of 66% (CI, 59% to 72%), and hs-cTnI concentrations less than 2 ng/L yielded an NPV of 68% (CI, 62% to 74%).

LIMITATION

Data were generated in a large single-center diagnostic study using central adjudication.

CONCLUSION

In symptomatic patients with CAD, very low hs-cTn concentrations, including hs-cTnI concentrations less than 2.5 ng/L, do not generally allow users to safely exclude inducible myocardial ischemia.

PRIMARY FUNDING SOURCE

European Union, Swiss National Science Foundation, Kommission für Technologie und Innovation (Innosuisse), Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University of Basel, University Hospital Basel, Roche, Abbott, and Singulex.

Direct Comparison of Cardiac Troponin T and I Using a Uniform and a Sex-Specific Approach in the Detection of Functionally Relevant Coronary Artery Disease

BACKGROUND

We aimed to directly compare high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) in the detection of functionally relevant coronary artery disease (fCAD).

METHODS

Consecutive patients referred with clinical suspicion of fCAD and no structural heart disease other than coronary artery disease were included. The presence of fCAD was based on rest/stress myocardial perfusion single-photon emission computed tomography/computed tomography and coronary angiography. hs-cTnI and hs-cTnT concentrations were measured in a blinded fashion. Diagnostic accuracy was quantified using the area under the ROC curve (AUC) and evaluated both for uniform use in all patients and for sex-specific use in women and men separately. The prognostic end point was major adverse cardiac events (MACEs; cardiovascular death or myocardial infarction) within 2 years. For the prognostic performance, we used a multivariable model comparison with the Akaike information criterion (AIC).

RESULTS

fCAD was detected in 613 of 2062 patients (29.7%) overall, 112 of 664 of women (16.9%), and 501 of 1398 of men (35.8%). hs-cTnI and hs-cTnT had comparable diagnostic accuracy when assessed for uniform use in all patients (AUC, 0.68 vs 0.66; P = 0.107) and separately in women (AUC, 0.68 vs 0.63; P = 0.068) and men (AUC, 0.65 vs 0.64; P = 0.475). However, women required lower rule-out cutoffs to achieve high sensitivity, and men needed higher rule-in cutoffs to achieve high specificity. hs-cTnI and hs-cTnT were strongly and independently associated with MACE within 2 years (P &lt; 0.001), with comparable prognostic accuracies by the AIC.

CONCLUSIONS

hs-cTnI and hs-cTnT provide moderate and comparable diagnostic accuracy. Sex-specific cutoffs may be preferred. The prognostic utility of both troponins is comparable.

Prospective Validation of a Biomarker-Based Rule Out Strategy for Functionally Relevant Coronary Artery Disease

BACKGROUND

This study aimed to prospectively advance a rule-out strategy for functionally significant coronary artery disease (CAD) by use of high-sensitivity cardiac troponin I (hs-cTnI) from bench to bedside, by application of a 3-step approach: validation in serum, correlation in plasma, and application on a clinical platform.

METHODS

Patients without known CAD referred for rest/stress myocardial perfusion single-photon emission tomography/computer tomography (MPI-SPECT/CT) were assigned to 3 consecutive cohorts: validation, correlation, and application. Functionally relevant CAD was adjudicated with the use of expert interpretation of MPI-SPECT/CT and, if available, coronary angiography. In the validation cohort resting hs-cTnI was measured in serum before stress testing with the research Erenna system, in serum and plasma in the correlation cohort with the research Erenna system, and in plasma in the application cohort with the clinical Clarity system.

RESULTS

Overall, functionally relevant CAD was adjudicated in 21% (304/1478) of patients. In the validation cohort (n = 613), hs-cTnI concentrations were significantly higher in patients with functionally relevant CAD (median 2.8 ng/L vs 1.9 ng/L, P &lt; 0.001) as compared to patients without functionally relevant CAD and allowed a rule out with 95% sensitivity in 14% of patients. In the correlation cohort (n = 606), hs-cTnI concentrations in serum and plasma strongly correlated (Spearman r = 0.921) and had similar diagnostic accuracy as quantified by the area under the receiver operating characteristic curve (0.686 vs 0.678, P = 0.425). In the application cohort (n = 555), very low hs-cTnI plasma concentrations (&lt; 0.5 ng/L) ruled out functionally relevant CAD with 95% sensitivity in 10% of patients.

CONCLUSIONS

A single resting plasma hs-cTnI measurement can safely rule out functionally relevant CAD in around 10% of patients without known CAD.

Heart Team: Joint Position of the Swiss Society of Cardiology and the Swiss Society of Cardiac Surgery

The Swiss Society of Cardiology (SSC) and the Swiss Society of Cardiac and Thoracic Vascular Surgery (SSCTVS) have formulated their mutual intent of a close, patient-oriented, and expertise-based collaboration in the Heart Team Paper. The interdisciplinary dialogue between the SSC and SSCTVS reflects an attitude in decision making, which guarantees the best possible therapy for the individual patient. At the same time, it is a cornerstone of optimized process quality, placing individual interests into the background.

Evaluation of the correct indication for a treatment is indeed very challenging and almost impossible to verify retrospectively. Quality in this very important health policy process can therefore only be assured by the use of mutually recognized indications, agreed upon by all involved physicians and medical specialties, whereby the capacity of those involved in the process is not important but rather their competence.

These two medical societies recognize their responsibility and have incorporated international guidelines as well as specified regulations for Switzerland. Former competitors now form an integrative consulting team able to deliver a comprehensive evaluation for patients. Naturally, implementation rests with the individual caregiver. The Heart Team Paperof the SGK and SGHC, has defined guide boards within which the involved specialists maintain sufficient room to maneuver, and patients have certainty of receiving the best possible therapy they require.

Diagnostic and Prognostic Value of Lead aVR During Exercise Testing in Patients Suspected of Having Myocardial Ischemia

We aimed to assess the diagnostic and prognostic value of ST-segment deviation in aVR, a lead often ignored in clinical practice, during exercise testing and to compare it to the most widely used criterion of ST-segment depression in V₅. We enrolled 1,596 patients with suspected myocardial ischemia referred for nuclear perfusion imaging undergoing bicycle stress testing. ST-segment amplitudes in leads aVR and V₅ were automatically measured. The presence of inducible myocardial ischemia was the diagnostic end point and adjudicated based on nuclear perfusion imaging and coronary angiography. Major adverse cardiac events (MACE) during 2 years of follow-up including death, acute myocardial infarction, and coronary revascularization were the prognostic end point. Exercise-induced myocardial ischemia was detected in 470 patients (29%). Median ST amplitudes for leads aVR and V₅ differed significantly among patients with and without ischemia (p <0.01). The diagnostic accuracy of ST changes for myocardial ischemia as quantified by the area under the receiver operating characteristic curve was highest 2 minutes into recovery and similar in aVR and V₅ (0.62, 95% confidence interval CI 0.60 to 0.65 vs 0.60, 95% confidence interval 0.58 to 0.63, p = 0.08 for comparison). In multivariate analysis, ST changes in lead aVR, but not lead V₅, contributed independent diagnostic information on top of clinical parameters and manual electrocardiographic interpretation. Within 2 years of follow-up, MACE occurred in 33% of patients with ST elevations in aVR and in 16% without (p <0.001). In conclusion, ST elevation in lead aVR during exercise testing indicates inducible myocardial ischemia independently of ST depressions in lead V₅ and clinical factors and also predicts MACE during follow-up.

Delayed release of brain natriuretic peptide to identify myocardial ischaemia

BACKGROUND

A recent pilot study suggested that exercise-induced myocardial ischaemia may lead to a delayed release of cardiac biomarkers, so that later sampling, for example, at 4 h after exercise could be used for diagnostic purpose.

MATERIALS AND METHODS

In an observational study, we enrolled 129 consecutive patients referred for evaluation of a suspected coronary artery disease by rest/stress myocardial perfusion single-photon emission computed tomography. The treating cardiologist used all available clinical information to quantify clinical judgment regarding the presence of myocardial ischaemia using a visual analogue scale twice: prior and after stress testing. BNP levels were determined in a blinded fashion at rest, at peak stress and 4 h after peak stress. The presence of myocardial ischaemia was adjudicated based on perfusion single-photon emission computed tomography and coronary angiography findings by an independent cardiologist.

RESULTS

Myocardial ischaemia was detected in 58 patients (45%). Patients with myocardial ischaemia had significantly higher BNP levels at all times, compared to patients without ischaemia: BNP rest (99 vs. 61 pg/mL P = 0·007), BNP stress (125 vs. 77 pg/mL P = 0·02) and BNP 4 h (114 vs. 71 pg/mL P = 0·018). Diagnostic accuracy as quantified by the area under the receiver operating characteristics curve (AUC) was moderate for all time points (AUC 0·64-0·66). The change in BNP between rest and 4 h did not provide added value, neither to the baseline BNP level nor to clinical judgment.

CONCLUSION

In contrast to our hypothesis, myocardial ischaemia did not lead to a differential delayed release of BNP. Late sampling did not seem clinically useful.

Red and NIR light dosimetry in the human deep brain

Photobiomodulation (PBM) appears promising to treat the hallmarks of Parkinson's Disease (PD) in cellular or animal models. We measured light propagation in different areas of PD-relevant deep brain tissue during transcranial, transsphenoidal illumination (at 671 and 808 nm) of a cadaver head and modeled optical parameters of human brain tissue using Monte-Carlo simulations. Gray matter, white matter, cerebrospinal fluid, ventricles, thalamus, pons, cerebellum and skull bone were processed into a mesh of the skull (158 × 201 × 211 voxels; voxel side length: 1 mm). Optical parameters were optimized from simulated and measured fluence rate distributions. The estimated μeff for the different tissues was in all cases larger at 671 than at 808 nm, making latter a better choice for light delivery in the deep brain. Absolute values were comparable to those found in the literature or slightly smaller. The effective attenuation in the ventricles was considerably larger than literature values. Optimization yields a new set of optical parameters better reproducing the experimental data. A combination of PBM via the sphenoid sinus and oral cavity could be beneficial. A 20-fold higher efficiency of light delivery to the deep brain was achieved with ventricular instead of transcranial illumination. Our study demonstrates that it is possible to illuminate deep brain tissues transcranially, transsphenoidally and via different application routes. This opens therapeutic options for sufferers of PD or other cerebral diseases necessitating light therapy.

[Phosphate nephropathy: how to avoid it?]

Colonoscopy is a commonly used procedure for colon cancer screening. The ideal bowel preparation for a good visualization of the colonic mucosa would be effective and well tolerated. Sodium phosphate (NaP) and polyethylen glycol (PEG) are the two most frequently used solutions in this indication. However, although NaP has been described as more effective and better tolerated, it can cause severe acute electrolytes disturbances and, in rare cases, lead to irreversible renal failure, called phosphate nephropathy. NaP should therefore be prescribed with caution and be formally banned for patients with risk factors.

Prevalence and predictors of depressive symptoms and wellbeing during and up to nine years after outpatient cardiac rehabilitation

BACKGROUND AND AIM

Depression is an important independent prognostic variable in cardiac patients. The prevalence and predictors of depressive symptoms up to nine years after cardiac rehabilitation were studied.

METHODS

Follow-up questionnaires were sent to 2199 patients who had completed a 12-week exercise-based outpatient cardiac rehabilitation (OCR) programme between June 1999 and March 2006. Medical outcome, general wellbeing, and depressive symptoms were assessed, the latter by using two screening questions according to Arrol. Patients with incomplete data due to language problems, lack of compliance and non-response were excluded.

RESULTS

Complete data for analysis was available for 710 patients. The median follow up period was 46 months (Interquartile range (IQR) 22-71, min. 6 months). At follow-up, 132 patients (19%) indicated low wellbeing, whereas 81 (11%) were having depressive symptoms. Multivariate analyses revealed impaired quality of life (p <0.001), diabetes (p = 0.013) and low exercise capacity after OCR (p = 0.003) to be independent predictors of low wellbeing at follow-up. Persistent smoking (p = 0.045) as well as negative mood (p = 0.022) at the end of OCR were independent predictors of depressive symptoms at follow-up.

CONCLUSIONS

In a selected patient population a mean of four years after OCR, persistent smoking, diabetes, low exercise capacity and impaired quality of life at the end of OCR were independent long term predictors of low wellbeing and depressive symptoms, rather than specific cardiac variables. This highlights the need for close cooperation between cardiovascular and psychological specialists in cardiac rehabilitation.

Dynamic assessment of right ventricular volumes and function by real-time three-dimensional echocardiography: a comparison study with magnetic resonance imaging in 100 adult patients

BACKGROUND

The aim of this study was to validate a novel real-time three-dimensional echocardiographic (RT3DE) analysis tool for the determination of right ventricular volumes and function in unselected adult patients.

METHODS

A total of 100 consecutive adult patients with normal or pathologic right ventricles were enrolled in the study. A dynamic polyhedron model of the right ventricle was generated using dedicated RT3DE software. Volumes and ejection fractions were determined and compared with results obtained on magnetic resonance imaging (MRI) in 88 patients with adequate acquisitions.

RESULTS

End-diastolic, end-systolic, and stroke volumes were slightly lower on RT3DE imaging than on MRI (124.0 +/- 34.4 vs 134.2 +/- 39.2 mL, P < .001; 65.2 +/- 23.5 vs 69.7 +/- 25.5 mL, P = .02; and 58.8 +/- 18.4 vs 64.5 +/- 24.1 mL, P < .01, respectively), while no significant difference was observed for ejection fraction (47.8 +/- 8.5% vs 48.2 +/- 10.8%, P = .57). Correlation coefficients on Bland-Altman analysis were r = 0.84 (mean difference, 10.2 mL; 95% confidence interval [CI], -31.3 to 51.7 mL) for end-diastolic volume, r = 0.83 (mean difference, 4.5 mL; 95% CI, -23.8 to 32.9 mL) for end-systolic volume, r = 0.77 (mean difference, 5.7 mL; 95% CI, -24.6 to 36.0 mL) for stroke volume, and r = 0.72 (mean difference, 0.4%; 95% CI, -14.2% to 15.1%) for ejection fraction.

CONCLUSION

Right ventricular volumes and ejection fractions as assessed using RT3DE imaging compare well with MRI measurements. RT3DE imaging may become a time-saving and cost-saving alternative to MRI for the quantitative assessment of right ventricular size and function.

[Noninvasive diagnostic of coronary artery disease]

Noninvasive imaging of coronary artery disease has extensively evolved during the last decade. Today, at least four imaging techniques with excellent image quality such as echocardiography, myocardial perfusion scintigraphy and PET, cardiac magnetic resonance and cardiac CT are widely available in order to estimate the risk for future ischemic events, to corroborate the suspected diagnosis of coronary artery disease, to demonstrate the extent and localisation of myocardial ischemia, to diagnose myocardial infarction and measure it's size, to identify the myocardium at risk during acute ischemia, to differentiate between viable and nonviable myocardium and thereby provide the basis for indications of revascularisations, to follow revascularized patients over long time, to assess the risk for sudden cardiac death and the development of heart failure after myocardial infarction and to depict atheromatosis and atherosclerosis of the coronary artery tree. Echocardiography is the most widely used imaging method in cardiology. It provides excellent information on morphology and function of nearly all cardiac structures. Stress echocardiography has been proven to be a reliable tool for the demonstration of myocardial ischemia and for the acquisition of prognostic data. Newer ultrasound techniques may further improve investigator dependence and thereby reproducibility. The completeness of echocardiography will always depend on acoustic windows, which are given in a specific patient. Myocardial perfusion scintigraphy provides the largest database especially on prognosis in coronary artery disease. It has been the <<work horse>> for the depictions of ischemic and infarcted myocardium. Radiation exposure will always be an issue. Newer hybrid techniques combining nuclear methods with cardiac CT may add arguments, which will be needed for clinical decision-making. Cardiac magnetic resonance has evolved as an important tool in the diagnosis of cardiovascular diseases. It is investigator independent, does not apply any biologically hazardous energy and has the largest potential for tissue characterization due to its high contrast resolution. It therefore is an excellent technique to investigate all the aspects of coronary artery disease. Its availability is increasing, however in order to fully utilize its large potential an optimal collaboration among -specialist (cardiologists, radiologists, physicists) is mandatory. Cardiac CT has evolved as an excellent method for the depiction of the coronary arteries. Due to its high spatial and time resolution it provides high quality luminography of the coronaries and newer technique are also -investigating plaque composition of diseased coronary arteries. Overestimation of coronary artery stenosis in calcified vessels is an inherent problem of the technique and the risk of radiation exposure has to be weighted against the benefit of non-invasively depicting the coronary arteries. It will be the future task of all specialists in this field to define the most efficient and cost-effective way to apply these excellent techniques for the investigation of all the different aspects of patients with coronary artery disease.

Impact of hemocontrol on hypertension, nursing interventions, and quality of life: a randomized, controlled trial

BACKGROUND

Volume overload contributes to the pathogenesis of hypertension in hemodialysis (HD) patients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

The Hemocontrol (HC) system (Gambro), which automatically adjusts ultrafiltration rate and dialysate conductivity during dialysis, has been suggested to improve hemodynamic tolerance and thereby facilitate fluid removal. A 6-mo randomized, controlled trial was performed to test the hypothesis that the addition of the HC system to a systematic BP management protocol may lower home BP in comparison with standard HD as primary end point. Secondary end points were the number of nursing interventions during dialysis and health-related quality of life.

RESULTS

Complete BP data were available for 36 of the 44 patients who completed the trial. There was a statistically significant overall decrease in systolic BP during the study period (P = 0.005). However, the difference between the HC group and the standard HD group was NS (HC: from 147.8 +/- 21.7 to 139.8 +/- 16.2 mmHg; standard HD: from 141.9 +/- 19.2 to 135.2 +/- 9.9 mmHg). The number of HD sessions that required nursing interventions decreased in the HC group, whereas it increased in the standard HD group (HC: 42.9% reduction; standard HD: 35.7% increase; P = 0.04). There was also a significant improvement in health-related quality of life in the HC group but not in the standard HD group.

CONCLUSIONS

These results suggest that the addition of the HC system to a systematic BP management protocol provides no additional benefit with regard to BP reduction. However, the HC system may improve the patient tolerability to dialysis.

Incremental cost-effectiveness of drug-eluting stents compared with a third-generation bare-metal stent in a real-world setting: randomised Basel Stent Kosten Effektivitäts Trial (BASKET)

BACKGROUND

No prospective trial-based data are available for incremental cost-effectiveness of drug-eluting stents (DES) compared with bare-metal stents (BMS) in unselected patients, as treated in everyday practice.

METHODS

The Basel stent cost-effectiveness trial (BASKET) included 826 consecutive patients treated with angioplasty and stenting for 1281 de-novo lesions, irrespective of indication for angioplasty. Patients were randomised to one of two DES (Cypher, n=264; Taxus, n=281) or to a cobalt-chromium-based BMS (Vision, n=281) and followed up for 6 months for occurrence of major adverse cardiac events and costs. Analysis was by intention-to-treat. The primary endpoint was cost-effectiveness after 6 months, with effectiveness defined as reduction of major adverse cardiac events.

FINDINGS

Cardiac death, myocardial infarction, or target vessel revascularisation occurred in 39 of 544 (7.2%) patients with DES and 34 of 280 (12.1%) with BMS (odds ratio 0.56, 95% CI 0.35-0.91; p=0.02), without significant differences between the two DES. Total costs at 6 months were higher with DES (mean 10,544, SD 6849) than with BMS (9639, 9067; p<0.0001); higher stent costs of DES were not compensated for by lower follow-up costs. Incremental cost-effectiveness ratio of DES compared with BMS to avoid one major event was 18,311, and costs per quality-adjusted life-year gained were more than 50 000. Subgroup analyses showed that DES were more cost-effective for elderly patients in specific high-risk groups.

INTERPRETATION

In a real-world setting, use of DES in all patients is less cost effective than in studies with selected patients. Use of these stents could be restricted to patients in high-risk groups.

Systemic Anticoagulation and Prevention of Hemodialysis Catheter Malfunction

Although chronic anticoagulation is commonly prescribed to prevent thrombosis and malfunction of hemodialysis tunneled cuffed catheters (TCC), there are only limited data regarding its efficacy. The aim of this prospective study was to evaluate whether anticoagulation with adjusted-dose warfarin targeting an international normalized ratio (INR) of 1.5-2.0 is associated with improved catheter outcome in long-term patients at high risk of TCC malfunction. Among the 65 patients included in the study, 35 were considered at high risk (i.e., patients with a history of previous TCC thrombosis requiring catheter replacement and/or with TCC malfunction occurring within 2 weeks after catheter insertion in the absence of mechanical problems) and were prescribed warfarin, whereas 30 low-risk patients did not receive anticoagulation. During follow-up, TCC malfunction, defined as the need for inversion of catheter lines and/or recombinant tissue-type plasminogen activator infusion, was observed in 61.5% of patients. Among patients receiving warfarin, 19 (54.3%) achieved adequate anticoagulation (i.e., > 80% of follow-up INR values and INR value at the time of malfunction within target range). Anticoagulation was considered inadequate in 16 patients (45.7%). Malfunction-free catheter survival at 9 months was 47.1% in patients with adequate anticoagulation compared with 8.1% in patients with inadequate anticoagulation (p = 0.01). This difference remained statistically significant after adjustment for aspirin intake. These results suggest that achieving adequate anticoagulation with target INR 1.5-2.0 may prevent TCC malfunction and improve catheter outcome.

Measurement of Blood Volume During Hemodialysis is a Useful Tool to Achieve Safely Adequate Dry Weight by Enhanced Ultrafiltration

Chronic fluid overload and hypertension are highly prevalent in the dialysis population. Measurement of blood volume (BV) during hemodialysis (HD) may prove useful to achieve dry weight (DW). Twelve (12) chronic hemodynamically stable dialysis patients were randomly selected to participate in a pilot study. BV changes were measured using an online blood volume monitor (Hemoscan, Gambro AB, Stockholm, Sweden). As part of an initial observation phase, the magnitude of BV variation (deltaBV) in percentage and total UF volume (UF) in liters were recorded for each dialysis session, and the deltaBV/UF ratio was calculated. DW was subsequently reduced by 0.5 kg in all patients and the tolerance of the procedure was assessed. Attempted DW reduction was successful in seven patients, whereas it resulted in hypotension or symptoms in the other five cases. The deltaBV/UF ratio was found to be significantly lower in patients in whom attempted DW reduction was successful (2.47%/L vs. 3.45%/L, P < 0.05). Using receiver operating characteristic (ROC) curve analysis, a deltaBV/UF ratio of less than 2.6%/L offered the best overall prediction of successful DW reduction. These results suggest that measurement of BV changes during HD and calculation of the deltaBV/UF ratio are valuable tools for management of DW in clinically stable patients.

Adjuvant chemotherapy for colon carcinoma with positive lymph nodes: use and benefit in routine health care practice

In 1990, an international consensus was reached on the efficacy of adjuvant chemotherapy for lymph node positive (stage III) colon carcinoma (CC). This study evaluates the use and benefit of such therapy in routine health care practice. The study includes all patients with stage III CC treated by putative curative surgery (n = 182) recorded at the Geneva cancer registry between 1990 and 1996. Factors modifying chemotherapy use were determined by logistic regression, considering patients with chemotherapy as cases (n = 55) and others as controls (n = 127). The effect of chemotherapy on the 5-year survival was evaluated by the Cox model. Analyses were adjusted for possible confounders. The use of chemotherapy increased over the period (P(trend) < 0.001). Age strongly modulated chemotherapy use. In 1996, 54% of eligible patients received chemotherapy, this proportion fell to 13% after age 70. Decisions to use chemotherapy significantly depended on stage, grade and cancer site. The chance to be treated was non-significantly lower among individuals of low social class, widowed and foreigners. Chemotherapy significantly decreased mortality rates (Hazard ratio: 0.35, 95%CI: 0.18-0.68), independently of the prognostic factors and with similar benefit regardless of stage and age group. Strong beneficial effect of adjuvant chemotherapy on stage III CC can be achieved in routine practice. However, this study shows that it is probably not optimally utilised in Switzerland, particularly among the elderly.

Absolute autofluorescence spectra of human healthy, metaplastic, and early cancerous bronchial tissue in vivo

Autofluorescence is emerging as a useful tool for the detection of early cancers in the bronchi. It has already produced interesting results, which have been implemented in commercial imaging devices. Their design relies on the spectroscopy of the tissues of interest. However, a large majority of these autofluorescence spectroscopy studies have been presented in arbitrary units. This is a drawback for, in particular, the designing of imaging devices based on autofluorescence. Using correction factors and a spectral sensitivity correction curve, we determined the absolute spectral distribution of the tissue autofluorescence in vivo. These measurements were performed on healthy, metaplastic, and dysplastic bronchial tissues at several excitation wavelengths ranging from 350 to 495 nm. Moreover, we measured at a fixed distance between the tissue and the probe to avoid geometric distortions of the spectra that are due to the optical characteristics of tissue. We found that the order of magnitude of the autofluorescence brightness was stable as the excitation wavelengths varied (on the order of 5 pW/muW x nm at the maximum of the fluorescence emission spectra).

In vivo autofluorescence spectroscopy of human bronchial tissue to optimize the detection and imaging of early cancers

We are developing an imaging system to detect pre-/early cancers in the tracheo-bronchial tree. Autofluorescence might be useful but many features remain suboptimal. We have studied the autofluorescence of human healthy, metaplastic and dysplastic/CIS bronchial tissue, covering excitation wavelengths from 350 to 480 nm. These measurements are performed with a spectrofluorometer whose distal end is designed to simulate the spectroscopic response of an imaging system using routine bronchoscopes. Our data provide information about the excitation and emission spectral ranges to be used in a dual range detection imaging system to maximize the tumor vs healthy and the tumor vs. inflammatory/metaplastic contrast in detecting pre-/early malignant lesions. We find that the excitation wavelengths yielding the highest contrasts are between 400 and 480 nm with a peak at 405 nm. We also find that the shape of the spectra of healthy tissue is similar to that of its inflammatory/metaplastic counterpart. Finally we find that, when the spectra are normalized, the region of divergence between the tumor and the nontumor spectra is consistently between 600 and 800 nm and that the transition wavelength between the two spectral regions is around 590 nm for all the spectra regardless of the excitation wavelength, thus suggesting that there might be one absorber or one fluorophore. The use of backscattered red light enhances the autofluorescence contrast.

Fluorescence pharmacokinetics of Lutetium Texaphyrin (PCI-0123, Lu-Tex) in the skin and in healthy and tumoral hamster cheek-pouch mucosa

We have investigated the pharmacokinetics (PK) of Lutetium Texaphyrin (Lu-Tex), a second-generation photosensitizer, in the Syrian hamster cheek pouch early cancer model. Ten male hamsters, five with chemically induced early squamous cell cancer of the left cheek pouch, received an intracardiac injection of a 10 mg/ml Lu-Tex solution, resulting in a dose of 12 mg Lu-Tex per kg of bodyweight. The PK of the dye have been measured during the 24 h following the injection with an optical-fiber-based spectrofluorometer on the ventral skin, the healthy and the tumoral cheek-pouch mucosa. The Lu-Tex fluorescence is excited at 460 nm and detected around 740 nm. All the measurements yield very similar pharmacokinetic curves. The fluorescence intensity reaches a maximum between two and three hours after the injection and, at its maximum, it is consistently higher (up to 1.5 times) on the tumor than on the healthy mucosa. It remains smaller on the skin than on cheek-pouch mucosa. After 24 h, the Lu-Tex fluorescence is no longer detectable either on the skin, on the lesion or on the healthy mucosa. Moreover, Lu-Tex clearly displays a significant fluorescence selectivity between early carcinoma and healthy mucosa in this model. Furthermore, the inter-animal fluctuations of the fluorescence signal are small (+/-16% on the tumor-bearing mucosa). Eight-minute-long skin-irradiation tests have been performed 24 h after the injection of the Lu-Tex on the ventral skin of 16 additional animals with a solar simulator. No reaction is observed, either macroscopically or microscopically, which further demonstrates, as suggested by the fluorescence measurements, that this photosensitizer is significantly cleared from the skin after 24 h.

5-Aminolevulinic acid and its derivatives: physical chemical properties and protoporphyrin IX formation in cultured cells

Protoporphyrin IX (PpIX) is used as a fluorescence marker and photosensitizing agent in photodynamic therapy (PDT). A temporary increase of PpIX in tissues can be obtained by administration of 5-aminolevulinic acid (ALA). Lipophilicity is one of the key parameters defining the bioavailability of a topically applied drug. In the present work, octanol-water partition coefficients of ALA and several of its esters have been determined to obtain a parameter related to their lipophilicity. The influence of parameters such as lipophilicity, concentration, time, and pH value on PpIX formation induced by ALA and its esters is then investigated in human cell lines originating from the lung and bladder. ALA esters are found to be more lipophilic than the free acid. The optimal concentration (c(opt), precursor concentration at which maximal PpIX accumulation is observed) is then measured for each precursor. Long-chained ALA esters are found to decrease the c(opt) value by up to two orders of magnitude as compared to ALA. The reduction of PpIX formation observed at higher concentrations than c(opt) is correlated to reduced cell viability as determined by measuring the mitochondrial activity. Under optimal conditions, the PpIX formation rate induced by the longer-chained esters is higher than that of ALA or the shorter-chained esters. A biphasic pH dependence on PpIX generation is observed for ALA and its derivatives. Maximal PpIX formation is measured under physiological conditions (pH 7.0-7.6), indicating that further enhancement of intracellular PpIX content may be achieved by adjusting the pharmaceutical formulation of ALA or its derivatives to these pH levels.

Pulse oximeter as a cause of skin burn during photodynamic therapy

Photodynamic therapy is increasingly being used for the treatment of various cancers. However, this technique has a major adverse effect, namely skin photosensitization. An unusual case of skin burn associated with pulse oximetry during photodynamic therapy in a patient treated for an early esophageal tumor is described. The patient, who was treated with mTHPC, suffered a second-degree burn on the index finger with subsequent loss of the nail. The only previously reported case of such a complication occurred with Photofrin, whereby no tissue other than skin was damaged.

Stability of the fluorescence measurement of Foscan in the normal human oral cavity as an indicator of its content in early cancers of the esophagus and the bronchi

Photodynamic therapy (PDT) with Foscan (mTHPC) is used to cure early cancers of the esophagus or the tracheobronchial tree. However, fixed PDT parameters (drug dose, light dose, etc.) do not permit an accurate prediction of the tissue damage. Large interpatient fluctuations in tissue drug level, at the time of light application, suggest that the light dose must be adjusted to the drug dose shortly before the PDT. This drug dose can be measured endoscopically by light-induced fluorescence spectroscopy, but this measurement is inconvenient and somewhat difficult. A better test site, yielding comparable information, is needed. The oral cavity seems ideal. However, it first had to be established to what extent the estimation of the drug dose was dependent upon the location of the measurement and the pressure applied to the probe. These measurements prove to be not only correlated to similar measurements in the esophagus or the bronchi but also more consistent and less sensitive to the location and the applied pressure. The buccal mucosa is therefore recommended as a test site for measuring the Foscan fluorescence signal at the time of PDT in the esophagus or the bronchi. This measurement is accurate enough for use in light-dose adjustment.

Photodetection of early human bladder cancer based on the fluorescence of 5-aminolaevulinic acid hexylester-induced protoporphyrin IX: a pilot study

Exogenous administration of 5-aminolaevulinic acid (ALA) is becoming widely used to enhance the endogenous synthesis of protoporphyrin IX (PpIX) in photodynamic therapy (PDT) and fluorescence photodetection (PD). Recently, results have shown that the chemical modification of ALA into its more lipophilic esters circumvents limitations of ALA-induced PpIX like shallow penetration depth into deep tissue layers and inhomogeneous biodistribution and enhances the total PpIX formation. The present clinical pilot study assesses the feasibility and the advantages of a topical ALA ester-based fluorescence photodetection in the human bladder. In this preliminary study 5-aminolaevulinic acid hexylester (h-ALA) solutions, containing concentrations ranging from 4 to 16 mM, were applied intravesically to 25 patients. Effects of time and drug dose on the resulting PpIX fluorescence level were determined in vivo with an optical fibre-based spectrofluorometer. Neither local nor systemic side-effects were observed for the applied conditions. All conditions used yielded a preferential PpIX accumulation in the neoplastic tissue. Our clinical investigations indicate that with h-ALA a twofold increase of PpIX fluorescence intensity can be observed using 20-fold lower concentrations as compared to ALA.

Pharmacokinetics of tetra(m-hydroxyphenyl)chlorin in human plasma and individualized light dosimetry in photodynamic therapy

The pharmacokinetics of the photosensitizer 5,10,15,20-tetra(m-hydroxyphenyl)chlorin (mTHPC) was investigated in the plasma of 20 patients by absorption and fluorescence spectroscopy. The temporal behavior was characterized by a rapid decrease in concentration during the first minutes after intravenous injection of 0.15 mg/kg mTHPC. A minimum concentration in the plasma was reached after about 45 min. The drug concentration then increased again, attaining a maximum after about 10 h, after which it decreased again with a halflife of about 30 h. Irradiation tests in the oral cavity at different time intervals after the injection revealed that the tissue reaction was only partially correlated with the mTHPC plasma level. The tissue response was stronger at later drug-light intervals (1-4 days) than during the first hours after injection even though the mTHPC plasma concentration was higher at the shorter times. Relative mTHPC concentrations were also measured in the mucosae of the oral cavity, the esophagus and the bronchi of 27 patients by light-induced fluorescence spectroscopy using an optical fiber-based spectrometer. These measurements were performed prior to photodynamic therapy (PDT), 4 days after injection of the photosensitizer. Highly significant linear correlations were found between the relative mTHPC concentrations in the mucosae of these three organs. Likewise, the plasma levels of mTHPC measured just before PDT were significantly correlated with the mTHPC concentrations in the three types of mucosae mentioned above. These results indicate that mTHPC plasma levels measured just before PDT can be used for PDT light dosimetry.

[Clinical value of bilateral measuring of blood pressure]

By describing six patients who present with a multitude of clinical signs we want to demonstrate the importance of bilateral blood pressure readings. In patients with repeated blood pressure differences in the two arms of greater than 20 mmHg [1] further examination by ultrasound and/or angiography is indicated.

An optical phantom with tissue-like properties in the visible for use in PDT and fluorescence spectroscopy

The design and characterization of optical phantoms which have the same absorption and scattering characteristics as biological tissues in a broad spectral window (between 400 and 650 nm) are presented. These low-cost phantoms use agarose dissolved in water as the transparent matrix. The latter is loaded with various amounts of silicon dioxide, Intralipid, ink, blood, azide, penicillin, bovine serum, and fluorochromes. The silicon dioxide and Intralipid particles are responsible for the light scattering whereas the ink and blood are the absorbers. The penicillin and the azide are used to ensure the conservation of such phantoms when stored at 4 degrees C. The serum and fluorochromes, such as Coumarin 30, produce an autofluorescence similar to human tissues. Various fluorochromes or photosensitizers can be added to these phantoms to simulate a cancer photodetection procedure. The absorption and fluorescence spectroscopy of the porphyrin-type fluorescent markers used clinically for such photodetection procedures is similar in these phantoms and in live tissues. The mechanical properties of these gelatinous phantoms are also of interest as they can easily be moulded and reshaped with a conventional cutter, so that complex structures and shapes, with different optical properties, can be designed. The optical properties of these phantoms were determined between 400 and 650 nm by measuring their effective attenuation coefficient (mu eff) and total reflectance (Rd). The microscopic absorption and reduced scattering coefficients (mu a, mu s') were deduced from mu eff and Rd using a Monte Carlo simulation.