Opportunistic prostate-specific antigen testing in Norwegian men: a public health challenge.

OBJECTIVE: To describe age-specific prostate-specific antigen (PSA) distributions and resulting prostate cancer diagnoses that arise from population-wide opportunistic PSA testing. PATIENTS AND METHODS: Over 8 million PSA tests were performed on >1.4 million Norwegian men from 2000 to 2020. During this period 43 486 men were diagnosed with localised prostate cancer. Most of the PSA testing reflected opportunistic testing. Age-specific PSA value distributions were constructed for men aged 45-75 years with and without prostate cancer. RESULTS: The distributions of PSA values in men with and without prostate cancer widened with age and overlapped extensively from 3 to 7 ng/mL. Localised prostate cancer diagnoses increased 10-fold from the age of 45 to 75 years. PSA testing identified intermediate- or high-grade cancers in 21% (95% confidence interval [CI] 19-23%) of men aged 50-54 years and 42% (95% CI 41-43%) of men aged 70-74 years. Grade group (GG)1, GG2, GG3 and ≥GG4 constituted 49%, 31%, 10% and 10% of cancers identified at age 50-54 years and 26%, 26%, 18%, and 30% of cancers identified at age 70-74 years. CONCLUSION: Opportunistic PSA testing increases with ageing and often generates values that cannot discriminate benign prostate enlargement from prostate cancer. A clinical cascade using additional imaging or serum tests is necessary to avoid negative biopsies and the overdiagnosis of indolent disease. The declining specificity of PSA testing with ageing poses a significant public health challenge especially among older men aged ≥70 years.

Baseline Serum Prostate-specific Antigen Value Predicts the Risk of Subsequent Prostate Cancer Death-Results from the Norwegian Prostate Cancer Consortium.

BACKGROUND: Prostate-specific antigen (PSA) levels in midlife are strongly associated with the long-term risk of lethal prostate cancer in cohorts not subject to screening. This is the first study evaluating the association between PSA levels drawn as part of routine medical care in the Norwegian population and prostate cancer incidence and mortality. OBJECTIVE: To determine the association between midlife PSA levels <4.0 ng/ml, drawn as part of routine medical care, and long-term risk of prostate cancer death. DESIGN, SETTING, AND PARTICIPANTS: The Norwegian Prostate Cancer Consortium collected >8 million PSA results from >1 million Norwegian males ≥40 yr of age. We studied 176 099 men (predefined age strata: 40-54 and 55-69 yr) without a prior prostate cancer diagnosis who had a nonelevated baseline PSA level (<4.0 ng/ml) between January 1, 1995 and December 31, 2005. INTERVENTION: Baseline PSA. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We assessed the 16-yr risk of prostate cancer mortality. We calculated the discrimination (C-index) between predefined PSA strata (<0.5, 0.5-0.9, 1.0-1.9, 2.0-2.9, and 3.0-3.9 ng/ml) and subsequent prostate cancer death. Survival curves were plotted using the Kaplan-Meier method. RESULTS AND LIMITATIONS: The median follow-up time of men who did not get prostate cancer was 17.9 yr. Overall, 84% of men had a baseline PSA level of <2.0 ng/ml and 1346 men died from prostate cancer, with 712 deaths (53%) occurring in the 16% of men with the highest baseline PSA of 2.0-3.9 ng/ml. Baseline PSA levels were associated with prostate cancer mortality (C-index 0.72 for both age groups, 40-54 and 55-69 yr). The fact that the reason for any given PSA measurement remains unknown represents a limitation. CONCLUSIONS: We replicated prior studies that baseline PSA at age 40-69 yr can be used to stratify a man's risk of dying from prostate cancer within the next 15-20 yr. PATIENT SUMMARY: A prostate-specific antigen level obtained as part of routine medical care is strongly associated with a man's risk of dying from prostate cancer in the next two decades.

Kinase activity profiling in renal cell carcinoma, benign renal tissue and in response to four different tyrosine kinase inhibitors.

Kinase activity is frequently altered in renal cell carcinoma (RCC), and tyrosine kinase inhibitors (TKIs) are part of the standard treatment strategy in patients with metastatic disease. However, there are still no established biomarkers to predict clinical benefits of a specific TKI. Here, we performed protein tyrosine kinase (PTK) profiling using PamChip® technology. The aim of this study was to identify differences in PTK activity between normal and malignant kidney tissue obtained from the same patient, and to investigate the inhibitory effects of TKIs frequently used in the clinics: sunitinib, pazopanib, cabozantinib and tivozanib. Briefly, our results showed that 36 kinase substrates differs (FDR < 0.05) between normal and cancer kidney tissue, where members of the Src family kinases and the phosphoinositide-3-kinase (PI3K) pathway exhibit high activity in renal cancer. Furthermore, ex vivo treatment of clear cell RCC with TKIs revealed that pathways such as Rap1, Ras and PI3K pathways were strongly inhibited, whereas the neurotrophin pathway had increased activity upon TKI addition. In our assay, tivozanib and cabozantinib exhibited greater inhibitory effects on PTK activity compared to sunitinib and pazopanib, implying they might be better suitable as TKIs for selected RCC patients.

Is time from diagnosis to radical prostatectomy associated with oncological outcomes?

PURPOSE: To study the association between time from diagnosis to radical prostatectomy (RP-interval) and prostate cancer-specific mortality (PCSM), histological findings in the RP-specimen and failure after RP (RP-failure). METHODS: Patients diagnosed with non-metastatic prostate cancer (PCa) in 2001-2010 and prostatectomized within 180 days of biopsy were identified in the Cancer Registry of Norway and the Norwegian Prostate Cancer Registry. Patients were stratified according to risk groups and RP-intervals of 0-60, 61-90, 91-120 and 121-180 days. Aalen-Johansen and Kaplan-Meier methods estimated curves for PCSM, RP-failure and overall mortality. Multivariable Cox regressions and Chi-square tests were used to evaluate the impact of RP-interval on outcomes. RESULTS: In 5163 eligible patients, the median time from diagnosis to RP was 93 days (range 1-180). Risk group distribution was similar in all RP-interval groups. With almost eight years of observation, no association was found between RP-interval and PCSM in the intermediate-or high-risk groups. Increasing RP-interval did not increase the rate of adverse histological outcomes or incidence of RP-failure. CONCLUSIONS: Increasing RP-interval up to 180 days was not associated with adverse oncological outcomes at eight years follow-up. These findings should be considered when planning for prostatectomy.

Poor reproducibility of PIRADS score in two multiparametric MRIs before biopsy in men with elevated PSA.

PURPOSE: Since January 2015, all men referred to urologists in Norway due to elevated PSA or other suspicion of prostate cancer underwent multiparametric MRI (mpMRI) before prostate biopsy. At our hospital, patients and the initial MRI were assessed by an urologist and if deemed necessary, patients were referred to another institution for MR/US fusion biopsies. Before MR/US biopsy, patients underwent a second mpMRI. Since we noticed disagreement of these two mpMRIs before biopsy, we retrospectively assessed the level of agreement between the two mpMRIs from the two institutions. METHODS: During the first 6 months of 2015, 292 patients were referred to our outpatient clinic. We referred 126 patients of these to the other institution for MR/US fusion biopsy. The 2 mpMRIs were performed within 4 weeks. We analyzed MR reports and schematics for number of lesions and highest PIRADS score per side of the prostate and histological result of the biopsies. Bland-Altman's plot was used to compare the level of agreement between the two mpMRIs of the same patient before biopsy. RESULTS: There was a poor level of agreement between the two mpMRIs and a statistically significant difference in PIRADS scores. Regression analysis showed that there was no proportional or systematic bias. CONCLUSION: In unselected patients with elevated PSA, there seems to be a significant variation of mpMRI results across institutions. The PIRADS scoring system needs to be validated with regards to MR equipment, mpMRI protocols and inter-reader variability of radiologists.

Pharmacological Treatment of Post-Prostatectomy Incontinence: What is the Evidence?

Urinary incontinence is a common and debilitating problem, and post-prostatectomy incontinence (PPI) is becoming an increasing problem, with a higher risk among elderly men. Current treatment options for PPI include pelvic floor muscle exercises and surgery. Conservative treatment has disputable effects, and surgical treatment is expensive, is not always effective, and may have complications. This article describes the prevalence and causes of PPI and the current treatment methods. We conducted a search of the PUBMED database and reviewed the current literature on novel medical treatments of PPI, with special focus on the aging man. Antimuscarinic drugs, phosphodiesterase inhibitors, duloxetine, and α-adrenergic drugs have been proposed as medical treatments for PPI. Most studies were small and used different criteria for quantifying incontinence and assessing treatment results. Thus, there is not enough evidence to recommend the use of these medications as standard treatment of PPI. To determine whether medical therapy is a viable option in the treatment of PPI, randomized, placebo-controlled studies are needed that also assess side effects in the elderly population.

Is robotic-assisted radical cystectomy (RARC) with intracorporeal diversion becoming the new gold standard of care?

BACKGROUND: Totally intracorporeal robotic-assisted radical cystectomy (RARC) has perceived difficulties compared to open radical cystectomy (ORC). As the technique is increasingly adopted around the world, the benefits of RARC with intra- or extracorporeal urinary diversion or ORC for the patients are still unclear. In this article, we consider the current evidence for this issue. METHODS: We assessed two questions through using expert opinion and the medical literature: (A) Is RARC better than ORC for removing the cancer surgery and outcome? (B) Is RARC better than ORC for the urinary diversion? OUTCOMES: (A) RARC is better than ORC for shorter length of stay, blood loss and complication rates. (B) Intracorporeal orthotopic neobladder may have a significant physiological and surgical benefit to the patient recovery. CONCLUSIONS: RARC with total intracorporeal reconstruction has potential benefits to the patient. We recommend that all surgeons document patient-related outcome measures, urodynamics and enhanced recovery protocols for cystectomy patients to help us understand the real improvements within bladder cancer surgery and reconstruction.

Robotic and minimal access surgery: technology and surgical outcomes of radical prostatectomy for prostate cancer.

Since the 1990s, minimal access surgery has been utilized in urology. In the past 15 years, robotic surgery has evolved and become a natural part of minimal access surgery. The dissemination has been fast and the opportunity of prospective trials has been missed. Nevertheless, robotic surgery has obvious benefits for the surgeon and patient. Even though the scientific evidence is not strong, robotic surgery is here to stay. However, there are lessons to learn from the implementation of the da Vinci system with regards to patient safety and prospective evaluation of the new technology. The future of surgery will include technologies derived from robotic surgery.

Quality of life and satisfaction with information after radical prostatectomy, radical external beam radiotherapy and postoperative radiotherapy: a long-term follow-up study.

AIMS AND OBJECTIVES: To assess patients' symptoms, quality of life and satisfaction with information three to four years after radical prostatectomy, radical external beam radiotherapy and postoperative radiotherapy and to analyse differences between treatment groups and the relationship between disease-specific, health-related and overall quality of life and satisfaction with information. BACKGROUND: Radical prostate cancer treatments are associated with changes in quality of life. Differences between patients undergoing different treatments in symptoms and quality of life have been reported, but there are limited long-term data comparing radical prostatectomy with radical external beam radiotherapy and postoperative radiotherapy. DESIGN: A cross-sectional survey design was used. METHODS: The study sample included 143 men treated with radical prostatectomy and/or radical external beam radiotherapy. Quality of life was measured using the 12-item Short Form Health Survey and the 50-item Expanded Prostate Cancer Index Composite Instrument. Questions assessing overall Quality of life and satisfaction with information were included. Descriptive statistics and interference statistical methods were applied to analyse the data. RESULTS: Radical external beam radiotherapy was associated with less urinary incontinence and better urinary function. There were no differences between the groups for disease-specific quality of life sum scores. Sexual quality of life was reported very low in all groups. Disease-specific quality of life and health-related quality of life were associated with overall quality of life. Patients having undergone surgery were more satisfied with information, and there was a positive correlation between quality of life and patient satisfaction. CONCLUSION: Pretreatment information and patient education lead to better quality of life and satisfaction. This study indicates a need for structured, pretreatment information and follow-up for all men going through radical prostate cancer treatment. RELEVANCE TO CLINICAL PRACTICE: Long-term quality of life effects should be considered when planning follow-up and information for men after radical prostate cancer treatment. Structured and organised information/education may increase preparedness for symptoms and bother after the treatment, improve symptom management strategies and result in improved quality of life.

Enhanced recovery after surgery: are we ready, and can we afford not to implement these pathways for patients undergoing radical cystectomy?

Enhanced recovery after surgery (ERAS) for radical cystectomy seems logical, but our study has shown a paucity in the level of clinical evidence. As part of the ERAS Society, we welcome global collaboration to collect evidence that will improve patient outcomes.

Guidelines for perioperative care after radical cystectomy for bladder cancer: Enhanced Recovery After Surgery (ERAS(®)) society recommendations.

PURPOSE: Enhanced recovery after surgery (ERAS) pathways have significantly reduced complications and length of hospital stay after colorectal procedures. This multimodal concept could probably be partially applied to major urological surgery. OBJECTIVES: The primary objective was to systematically assess the evidence of ERAS single items and protocols applied to cystectomy patients. The secondary objective was to address a grade of recommendation to each item, based on the evidence and, if lacking, on consensus opinion from our ERAS Society working group. EVIDENCE ACQUISITION: A systematic literature review was performed on ERAS for cystectomy by searching EMBASE and Medline. Relevant articles were selected and quality-assessed by two independent reviewers using the GRADE approach. If no study specific to cystectomy was available for any of the 22 given items, the authors evaluated whether colorectal guidelines could be extrapolated. EVIDENCE SYNTHESIS: Overall, 804 articles were retrieved from electronic databases. Fifteen articles were included in the present systematic review and 7 of 22 ERAS items were studied. Bowel preparation did not improve outcomes. Early nasogastric tube removal reduced morbidity, bowel recovery time and length of hospital stay. Doppler-guided fluid administration allowed for reduced morbidity. A quicker bowel recovery was observed with a multimodal prevention of ileus, including gum chewing, prevention of PONV and minimally invasive surgery. CONCLUSIONS: ERAS has not yet been widely implemented in urology and evidence for individual interventions is limited or unavailable. The experience in other surgical disciplines encourages the development of an ERAS protocol for cystectomy.

Predicting erectile function outcome in men after radical prostatectomy for prostate cancer.

OBJECTIVE: • To identify the reported rates of potency after prostatectomy in the recent literature for men without preoperative erectile dysfunction (ED) and to develop a statistical model for predicting the expected potency after prostatectomy. MATERIALS AND METHODS: • A Medline search was conducted with the keywords 'potency' and 'prostatectomy' from 2003 to 2009. • In total, 33 studies in the English language reporting pre- and postoperative erectile function were identified. • Data from studies reporting outcome after open, laparoscopic and robot-assisted prostatectomy were analyzed separately. • Only data obtained from potent men before surgery were included in the analysis. RESULTS: • In potent men before surgery, the main predictors of post-treatment erectile function are age and time after treatment. • The cumulative range of potency rates at 48 months for all ages (45-75 years) was 49-74% for open, 58-74% for laparoscopic and 60-100% for robotic prostatectomy. • The predicted outcome differs by type of operation and patient age. CONCLUSIONS: • Men aged <60 years have a significant likelihood of regaining erectile function after radical prostatectomy. • The reported statistical model provides a reliable estimation of erectile function outcome after prostatectomy for men with localized prostate cancer and intact erectile function.

Oxygen-wasting effect of inotropy: is there a need for a new evaluation? An experimental large-animal study using dobutamine and levosimendan.

BACKGROUND: We addressed the hypothesis that the inotropic drugs dobutamine and levosimendan both induce surplus oxygen consumption (oxygen wasting) relative to their contractile effect in equipotent therapeutic doses, with levosimendan being energetically more efficient. METHODS AND RESULTS: Postischemically reduced left ventricular function (stunning) was created by repetitive left coronary occlusions in 22 pigs. This contractile dysfunction was reversed by infusion of either levosimendan (24 microg/kg loading and 0.04 microg x kg(-1) x min(-1) infusion) or an equipotent dose of dobutamine (1.25 microg x kg(-1) x min(-1)). Contractility and cardiac output were normalized by both drug regimens. The energy cost of drug-induced contractility enhancement was assessed by myocardial oxygen consumption related to the mechanical indexes tension-time index, pressure-volume area, and total mechanical energy. ANCOVA did not reveal any increased oxygen cost of contractility for either drug in these doses. However, both dobutamine and levosimendan at supratherapeutic levels (10 microg x kg(-1) x min(-1) and 48 microg/kg loading with 0.2 microg x kg(-1) x min(-1) infusion, respectively) induced a highly significant increase in oxygen consumption related to mechanical work, compatible with the established oxygen-wasting effect of inotropy (P<0.001 for all mechanical indexes with dobutamine; P=0.007 for levosimendan as assessed by pressure-volume area). CONCLUSIONS: Therapeutic levels of neither dobutamine nor levosimendan showed inotropic oxygen wasting in this in vivo pig model. Thus, relevant hemodynamic responses can be achieved with an adrenergic inotrope without surplus oxygen consumption.

Left ventricular size determines tissue Doppler-derived longitudinal strain and strain rate.

AIMS: Tissue Doppler-derived indices of strain (epsilon) and strain rate (SR) have been developed to assess regional cardiac function. However, the effect of left ventricular (LV) size on epsilon and SR has not been studied in depth. The aim of this study was to assess to what extent heart size influence epsilon or SR. METHODS AND RESULTS: In 21 anaesthetized pigs ranging from 12.5 to 70.0 kg, tissue Doppler-derived epsilon and SR, and haemodynamic parameters, were assessed during controlled heart rates and different loading conditions. dP/dt did not correlate to pig weight, suggesting constant contractility during growth. Longitudinal epsilon and SR were significantly higher in smaller compared with larger hearts. The hyperbolic correlation between pigs weight and epsilon and SR was r(2)=0.621 and 0.372, respectively, both P<0.0001. Afterload elevation induced a reduction in longitudinal epsilon (from -24.2+/-3.2 to -12.1+/-5.5%, P=0.001) and SR (from -2.3+/-0.8 to -1.3+/-2.4 s(-1), P=0.034), whereas increasing preload increased epsilon (from -26.4+/-10.3 to -38.1+/-14.3%, P=0.006) and SR (from -2.3+/-0.9 to -4.22+/-1.8 s(-1), P=0.002). CONCLUSION: Longitudinal epsilon and SR decrease with increasing LV dimensions in spite of an unaltered contractility. These results show and confirm that heart size influences epsilon and SR, which are highly load-dependent parameters.

Utilization and outcome of coronary revascularization and valve procedures in acute heart failure--an evaluation based on the classification from the European Society of Cardiology.

Early invasive treatments in patients with acute heart failure (AHF) are critical components to improve outcome. We aimed to establish if such treatments were applied according to existing guidelines and also to assess the subsequent mortality in the complete AHF population. All patients with AHF admitted to the intensive care unit/coronary care unit during the years 2003-2004 (n=302) were retrospectively reviewed and classified according to the European Society of Cardiology. Invasive revascularization was applied more frequently in patients with cardiogenic shock following acute coronary syndromes (78%, n=40) than in less severe AHF (58%, n=62, P<0.05). Only 8% (n=4) of eligible patients with acute coronary syndromes and cardiogenic shock were treated non-invasively. Valvular dysfunction was a precipitating factor for AHF in 15% (n=38). Acute mitral regurgitation was treated surgically exclusively in patients with mechanical defects. In-hospital mortality rates for less severe AHF was 12%, cardiogenic shock 46% and postcardiotomy HF 32%. Invasively treated patients had lower in-hospital mortality in both cardiogenic shock (35% vs. 70%, P=0.006) and less severe AHF (6% vs.17%, P=0.042). The study revealed an appropriate use of invasive revascularization. The high mortality in patients with severe AHF indicates that more effective treatment options are needed in eligible patients.

How many acute heart failure patients need a ventricular assist device?

OBJECTIVES: The most severe forms of acute heart failure have a dismal prognosis despite modern invasive treatment. For some of these patients, improved outcome must relay on early institution of ventricular assist devices (VAD). We aimed to estimate the potential VAD need in acute heart failure. DESIGN: All patients admitted to the ICU or CCU for acute heart failure (AHF) in 2003/04 (n=302) were reviewed. Non-survivors with severe acute heart failure, i.e. cardiogenic shock and postcardiotomy HF, were individually reviewed to assess eligibility for VAD-treatment. RESULTS: Cardiogenic shock and postcardiotomy HF was present in 23% (n=69) and 19% (n=57) of the AHF patients. Overall in hospital mortality in these groups was 38% (n=48). Of these, 15 were less than 75 years of age, without serious comorbidities and thus deemed to be potential candidates for VAD-treatment. CONCLUSION: This survey indicates that 12% of patients with severe acute heart failure are potential candidates for VAD-treatment. Extending these figures to a national level, indicate that approximately 70 patients per year could be candidates for short-term VAD-treatment in Norway.

Vasopressin impairs brain, heart and kidney perfusion: an experimental study in pigs after transient myocardial ischemia.

INTRODUCTION: Arginine vasopressin (AVP) is increasingly used to restore mean arterial pressure (MAP) in low-pressure shock states unresponsive to conventional inotropes. This is potentially deleterious since AVP is also known to reduce cardiac output by increasing vascular resistance. The effects of AVP on blood flow to vital organs and cardiac performance in a circulation altered by cardiac ischemia are still not sufficiently clarified. We hypothesised that restoring MAP by low dose, therapeutic level AVP would reduce vital organ blood flow in a setting of experimental acute left ventricular dysfunction. METHODS: Cardiac output (CO) and arterial blood flow to the brain, heart, kidney and liver were measured in nine pigs using transit-time flow probes. Left ventricular pressure-volume catheter and central arterial and venous catheters were used for haemodynamic recordings and blood sampling. Transient left ventricular ischemia was induced by intermittent left coronary occlusions resulting in a 17% reduction in cardiac output and a drop in MAP from 87 +/- 3 to 67 +/- 4 mmHg (p < 0.001). A low-dose therapeutic level of AVP (0.005 U/kg/min) was used to restore MAP to pre-ischemic values (93 +/- 4 mmHg). RESULTS: AVP further impaired systemic perfusion (CO and brain, heart and kidney blood flow reduced by 29, 18, 23 and 34%, respectively) due to a 2.0-, 2.2-, 1.9- and 2.1-fold increase in systemic, brain, heart and kidney specific vascular resistances. The hypoperfusion induced by AVP was associated with an increased systemic oxygen extraction. Oxygen saturation in blood drawn from the great cardiac vein fell from 29 +/- 1 to 21 +/- 3% (p = 0.01). Finally, these effects were reversed 40 min after AVP was withdrawn. CONCLUSION: Low dose AVP induced a pronounced reduction in vital organ blood flow in pigs after transient cardiac ischemia. This indicates a potentially deleterious effect of AVP in patients with heart failure or cardiogenic shock due to impaired coronary perfusion.

Adenosine instead of supranormal potassium in cardioplegic solution improves cardioprotection.

OBJECTIVE: To determine whether adenosine instead of supranormal potassium in cold crystalloid cardioplegia gives satisfactory cardiac arrest and improved cardioprotection. Cold crystalloid cardioplegia with adenosine, procaine and magnesium (A) was compared with standard cold crystalloid hyperkalemic cardioplegia (K). METHODS: Sixteen pigs were randomized to receive either cold K (n=8) or A (n=8), where hyperkalemia was substituted with 1.2 mM adenosine. The cold (6 degrees C) cardioplegia was given intermittently and antegradely, with an aortic cross-clamp time of 1 h. Hemodynamic data was continuously measured and pressure-volume conductance catheters were used to determine global left ventricular systolic and diastolic function. Coronary flow and O2 content differences allowed determination of left ventricular energetics. Blood samples, and left ventricular microdialysis were used to measure parameters of ischemia. Measurements were done at 1 and 2 h after cross-clamp release. RESULTS: Mean arterial pressure was reduced with 55 mmHg (standard deviation, SD: 19) in the K group versus 30 mmHg (SD: 14) in the A group 2 h after cross-clamp release (p=0.030). Left ventricular contractility expressed as slope of the preload recruitable stroke work index (Mw) was reduced to 53% (SD: 14) in the K group versus 78% (SD: 23) in the A group 2h after cross-clamp release (p=0.046). Reduction of maximum of first derivate of pressure with respect to time (dP/dtmax) was 804 mmHg/s (SD: 189) in the K group versus 538 mmHg/s (SD: 184) in the A group (p=0.033). The slope of the myocardial oxygen consumption-pressure volume area was at 2 h reperfusion increased from 1.37 (SD: 0.64) to 2.86 (SD: 1.27) in the K group, whereas no shift was detected in the A group (p=0.019). Cardiac troponin T measured in the coronary sinus 1 h after cross-clamp release was 1.25 microg/l (SD: 0.64) in the K group versus 0.73 microg/l (SD: 0.31) in the A group (p=0.046). CONCLUSION: Adenosine instead of supranormal potassium in cold crystalloid cardioplegia gives satisfactory cardiac arrest, improves post cardioplegic left ventricular systolic function and efficiency, and attenuates myocardial cell damage.

Mechanical restitution curves: a possible load independent assessment of contractile function.

OBJECTIVE: The time constant of mechanical restitution (T((MRC))), proposed to reflect changes in calcium release and uptake, has been shown to increase in left ventricular (LV) failure, and might have a potential as an index of contractile function. However, in vivo studies of the effect on T((MRC)) of changing loading conditions in the normal and failing heart have not been reported. Consequently, in this study, we tested the hypothesis that the increase in T((MRC)) in vivo is independent of preload and afterload. METHODS: Left ventricular pressure-volume loops were assessed at baseline in eight open chest pigs using the combined pressure-volume conductance catheter technique during right atrial pacing at 120b/min. Mechanical restitution curves (MRC) were constructed during four different loading conditions in all eight animals: uninfluenced load, reduced preload (balloon catheter in v. cava inferior), increased afterload (balloon catheter in descending aorta), and increased preload combined with reduced afterload (aortocaval shunting). Acute LV failure was then induced by microembolization through the left main coronary artery, and the experimental protocol was repeated. Contractile response was defined as the maximal first derivative of pressure (dP/dt(max)), and T((MRC)) was calculated using a least square approximation algorithm. RESULTS: Hemodynamic data 30min after microembolization showed decreased mean arterial pressure (98+/-14-67+/-10mmHg, (mean+/-SD) P<0.0001) and dP/dt(max) (1482+/-193-1001+/-125mmHg/s, P=0.001). Stroke volume decreased from 30+/-5 to 20+/-5ml (P<0.0001) compared to baseline, and preload recruitable stroke work decreased from 52+/-7 to 31+/-10mmHg (P=0.002). T((MRC)) increased in all eight animals after induction of LV failure at all loading conditions. There was no difference between the different loading conditions at baseline, nor at LV heart failure, but T((MRC)) increased significantly after the induction of heart failure (ANOVA, two ways). CONCLUSIONS: We have shown that the left ventricular T((MRC)) increases after developed heart failure. The increase in T((MRC)) was independent on loading conditions and thus have a potential for a contractility index.

The pressure-volume loop revisited: Is the search for a cardiac contractility index a futile cycle?

UNLABELLED: Our previous studies indicate that left ventricular end-systolic pressure-volume relations (ESPVRs) or elastance (Ees) are not reduced in studies where expected reductions of contractility should be found (i.e., heart failure, stunning, and endotoxemia). The present study was done to assess whether this phenomenon is due to a particular load sensitivity of elastance, rendering this index inappropriate as a measurement of contractility in pathologic states in vivo. METHODS AND RESULTS: Analysis of previously generated data revealed an increased ESPVR in stunned hearts, in pigs made endotoxemic, and in hearts rapidly paced. After inducing acute heart failure by microembolization, the ESPVR was increased when assessed using linear relations but reduced when assessing ESPVR by a curvilinear algorithm. To further evaluate the effect of different load alterations on ESPVR, this relation was generated by (i) inferior vena caval occlusions (VCOs); (ii) gradually occluding the descending aorta (pressure interventions); and (iii) rapidly infusing blood (120 mL) into the left atrium (volume increments). The load protocol was applied in 5 pigs, before and after the left ventricle was stunned by 11 brief left main coronary artery occlusions/reperfusions (accumulated ischemia 20 min affecting 81% of the left ventricle). Correlation coefficients for left ventricular elastance ranged from 0.93 to 0.99 in all the 3 types of loading interventions. Despite significant reductions in stroke volume, stroke work, and dP/dtmax, VCO-calculated linear and curvilinear Ees increased 90 min after stunning (55% +/- 4% and 94% +/- 6%, respectively). Linear Ees during pressure interventions decreased 36% +/- 1%, whereas curvilinear Ees decreased 33% +/- 3%. During volume infusions, linear Ees decreased 27% +/- 2%. We achieved the same results after blocking the baroreceptor reflexes using hexamethonium. CONCLUSIONS: The Ees is particularly load dependent and will reflect load interventions more than the inotropic state of the cardiac muscle. A VCO-generated Ees increase could be an unmasking of a pronounced preload sensitivity in failing myocardium.