Patients' experiences of clinical trial participation involving a product remotely assessing study drug adherence.

Background: The participation of patients in clinical trials is crucial for the development of healthcare. There are several challenges in the recruitment of trial participants with acute medical conditions. The registry-based randomized DAPA-MI clinical trial recruited patients during hospitalization for myocardial infarction and provided study drugs in bottles with smart caps that used wireless technology to transmit monitoring data. This interview study aimed to investigate patients' experience of participation in a clinical trial and their attitude to the new bottle cap technology. Methods: A subset of patients participating in the DAPA-MI trial were recruited from four hospitals in Sweden. Semi-structured interviews were conducted and analysed using manifest content analysis. Results: Video interviews were performed including 21 patients (four women and 17 men). The median age was 59 years (range 44-80). Four categories of patients' experiences were identified. A willingness to contribute consisted of patients' positive attitudes to participation and to be a part of development and research. The perception of information emphasized the value of the oral information as well as the importance of time for reflection. Be in a vulnerable condition highlighted the impaired ability to perceive and remember in the acute medical condition. Adaptation to a new technology described the overall positive experiences of the smart bottle cap to evaluate adherence. Conclusions: Patients' experiences of trial participation were in general positive but some challenges in the acute setting of a myocardial infarction were revealed. The smart bottle cap was well accepted, despite some handling difficulties.

Limb Outcomes With Ticagrelor Plus Aspirin in Patients With Diabetes Mellitus and Atherosclerosis.

BACKGROUND: Ticagrelor reduced major adverse cardiovascular events (MACE) and increased bleeding in patients with type 2 diabetes mellitus (T2DM) and coronary artery disease. Limb events including revascularization, acute limb ischemia (ALI), and amputation are major morbidities in patients with T2DM and atherosclerosis. OBJECTIVES: This study sought to determine the effect of ticagrelor on limb events. METHODS: Patients were randomized to ticagrelor or placebo on top of aspirin and followed for a median of 3 years. MACE (cardiovascular death, myocardial infarction, or stroke), limb events (ALI, amputation, revascularization), and bleeding were adjudicated by an independent and blinded clinical events committee. The presence of peripheral artery disease (PAD) was reported at baseline. RESULTS: Of 19,220 patients randomized, 1,687 (8.8%) had PAD at baseline. In patients receiving placebo, PAD was associated with higher MACE (10.7% vs 7.3%; HR: 1.48; P < 0.001) and limb (9.5% vs 0.8%; HR: 10.67; P < 0.001) risk. Ticagrelor reduced limb events (1.6% vs 1.3%; HR: 0.77; 95% CI: 0.61-0.96; P = 0.022) with significant reductions for revascularization (HR: 0.79; 95% CI: 0.62-0.99; P = 0.044) and ALI (HR: 0.24; 95% CI: 0.08-0.70; P = 0.009). The benefit was consistent with or without PAD (HR: 0.80; 95% CI: 0.58-1.11; and HR: 0.76; 95% CI: 0.55-1.05, respectively; Pinteraction = 0.81). There was no effect modification of ticagrelor vs placebo based on PAD for MACE (Pinteraction = 0.40) or TIMI major bleeding (Pinteraction = 0.3239). CONCLUSIONS: Patients with T2DM and atherosclerosis are at high risk of limb events. Ticagrelor decreased this risk, but increased bleeding. Future trials evaluating the combination of ticagrelor and aspirin would further elucidate the benefit/risk of such therapy in patients with PAD, including those without coronary artery disease. (A Study Comparing Cardiovascular Effects of Ticagrelor Versus Placebo in Patients With Type 2 Diabetes Mellitus [THEMIS]: NCT01991795).

Dapagliflozin in Myocardial Infarction without Diabetes or Heart Failure.

BACKGROUND: In patients with acute myocardial infarction (MI), therapies that could further reduce the risk of adverse cardiovascular and metabolic outcomes are needed. METHODS: In this international registry-based, randomized, double-blind trial, patients without prior diabetes or chronic heart failure, presenting with acute MI and impaired left ventricular systolic function, were randomly assigned 10 mg of dapagliflozin or placebo, given once daily. The primary outcome was the hierarchical composite of death, hospitalization for heart failure, nonfatal MI, atrial fibrillation/flutter, type 2 diabetes mellitus, New York Heart Association Functional Classification at the last visit, and body weight decrease of 5% or greater at the last visit using the win ratio analysis method. The key secondary outcome was the same hierarchical composite excluding the body weight component. RESULTS: We enrolled 4017 patients of whom 2019 were assigned to dapagliflozin and 1998 to placebo. The analysis of the primary hierarchical composite outcome resulted in significantly more wins for dapagliflozin than for placebo (win ratio, 1.34; 95% confidence interval [CI], 1.20 to 1.50; P<0.001). The win ratio outcome, which was adopted in a change of analysis during trial performance because of low event accrual, was mainly driven by the added cardiometabolic outcomes. The composite of time to cardiovascular death/hospitalization for heart failure occurred in 50/2019 (2.5%) patients assigned to dapagliflozin and 52/1998 (2.6%) patients assigned to placebo (hazard ratio, 0.95; 95% CI, 0.64 to 1.40). The rates of other cardiovascular events were low, with differences between the groups not reaching nominal statistical significance. No safety concerns were identified. CONCLUSIONS: In patients with acute MI as noted above, after approximately 1 year of treatment with dapagliflozin there were significant benefits with regard to improvement in cardiometabolic outcomes but no impact on the composite of cardiovascular death or hospitalization for heart failure compared with placebo. (Funded by AstraZeneca; ClinicalTrial.gov number, NCT04564742.)

Rationale and design of the DAPA-MI trial: Dapagliflozin in patients without diabetes mellitus with acute myocardial infarction.

BACKGROUND: Therapies that could further prevent the development of heart failure (HF) and other cardiovascular and metabolic events in patients with recent myocardial infarction (MI) represent a large and unmet medical need. METHODS: DAPA-MI is a multicenter, parallel-group, registry-based, randomized, double-blind, placebo-controlled phase 3 trial in patients without known diabetes or established HF, presenting with MI and impaired left ventricular systolic function or Q-wave MI. The trial evaluated the effect of dapagliflozin 10 mg vs placebo, given once daily in addition to standard of care therapy, on death, hospitalization for HF (HHF), and other cardiometabolic outcomes. The primary objective of the trial was to determine, using the win-ratio method, if dapagliflozin is superior to placebo by comparing the hierarchical composite outcome of death, HHF, nonfatal MI, atrial fibrillation/flutter, new onset of type 2 diabetes mellitus, HF symptoms as measured by New York Heart Association Functional Classification at last visit, and body weight decrease ≥5% at last visit. Assuming a true win-ratio of 1.20 between dapagliflozin and placebo, 4,000 patients provide a statistical power of 80% for the test of the primary composite outcome. A registry-based randomized controlled trial framework allowed for recruitment, randomization, blinding, and pragmatic data collection of baseline demographics, medications, and clinical outcomes using existing national clinical registries (in Sweden and the UK) integrated with the trial database. CONCLUSIONS: The trial explores opportunities to improve further the outcome of patients with impaired LV function after MI. The innovative trial design of DAPA-MI, incorporating national clinical registry data, has facilitated efficient patient recruitment as well as outcome ascertainment. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT04564742.

Cost-effectiveness of ticagrelor in patients with type 2 diabetes and coronary artery disease: a European economic evaluation of the THEMIS trial.

AIMS: To conduct a health economic evaluation of ticagrelor in patients with type 2 diabetes and coronary artery disease (CAD) from a multinational payer perspective. Cost-effectiveness and cost-utility of ticagrelor were evaluated in the overall effect of Ticagrelor on Health Outcomes in Diabetes Mellitus Patients Intervention Study (THEMIS) trial population and in the predefined patient group with prior percutaneous coronary intervention. METHODS AND RESULTS: A Markov model was developed to extrapolate patient outcomes over a lifetime horizon. The primary outcome was incremental cost-effectiveness ratios (ICERs), which were compared with conventional willingness-to-pay thresholds [€47 000/quality-adjusted life-year (QALY) in Sweden and €30 000/QALY in other countries].Treatment with ticagrelor resulted in QALY gains of up to 0.045 in the overall population and 0.099 in patients with percutaneous coronary intervention (PCI). Increased costs and benefits translated to ICERs ranged between €27 894 and €42 252/QALY across Sweden, Germany, Italy, and Spain in the overall population. In patients with prior PCI, estimated ICERs improved to €18 449, €20 632, €20 233, and €13 228/QALY in Sweden, Germany, Italy, and Spain, respectively, driven by higher event rates and treatment benefit. CONCLUSION: Based on THEMIS results, ticagrelor plus aspirin compared with aspirin alone may be cost-effective in some European countries in patients with T2DM and CAD and no prior myocardial infarction (MI) or stroke. Additionally, ticagrelor is likely to be cost-effective across European countries in patients with a history of PCI.

Diabetes-Related Factors and the Effects of Ticagrelor Plus Aspirin in the THEMIS and THEMIS-PCI Trials.

BACKGROUND: THEMIS (The Effect of Ticagrelor on Health Outcomes in Diabetes Mellitus Patients Intervention Study) (n = 19,220) and its pre-specified THEMIS-PCI (The Effect of Ticagrelor on Health Outcomes in Diabetes Mellitus Patients Intervention Study-Percutaneous Coronary Intervention) (n = 11,154) subanalysis showed, in individuals with type 2 diabetes mellitus (median duration 10.0 years; HbA1c 7.1%) and stable coronary artery disease without prior myocardial infarction (MI) or stroke, that ticagrelor plus aspirin (compared with placebo plus aspirin) produced a favorable net clinical benefit (composite of all-cause mortality, MI, stroke, fatal bleeding, and intracranial bleeding) if the patients had a previous percutaneous coronary intervention. OBJECTIVES: In these post hoc analyses, the authors examined whether the primary efficacy outcome (cardiovascular death, MI, stroke: 3-point major adverse cardiovascular events [MACE]), primary safety outcome (Thrombolysis In Myocardial Infarction-defined major bleeding) and net clinical benefit varied with diabetes-related factors. METHODS: Outcomes were analyzed across baseline diabetes duration, HbA1c, and antihyperglycemic medications. RESULTS: In THEMIS, the incidence of 3-point MACE increased with diabetes duration (6.7% for ≤5 years, 11.1% for >20 years) and HbA1c (6.4% for ≤6.0%, 11.8% for >10.0%). The relative benefits of ticagrelor plus aspirin on 3-point MACE reduction (hazard ratio [HR]: 0.90; p = 0.04) were generally consistent across subgroups. Major bleeding event rate (overall: 1.6%) did not vary by diabetes duration or HbA1c and was increased similarly by ticagrelor across all subgroups (HR: 2.32; p < 0.001). These findings were mirrored in THEMIS-PCI. The efficacy and safety of ticagrelor plus aspirin did not differ by baseline antihyperglycemic therapy. In THEMIS-PCI, but not THEMIS, ticagrelor generally produced favorable net clinical benefit across diabetes duration, HbA1c, and antihyperglycemic medications. CONCLUSION: Ticagrelor plus aspirin yielded generally consistent and favorable net clinical benefit across the diabetes-related factors in THEMIS-PCI but not in the overall THEMIS population.

Safety and Cumulative Incidence of Major Cardiovascular Events with Ticagrelor in Taiwanese Patients with Non-ST-Segment Elevation Myocardial Infarction: A 12-Month, Prospective, Phase IV, Multicenter, Single-Arm Study.

BACKGROUND: Ticagrelor, an oral, direct-acting, and reversible P2Y12 receptor antagonist, inhibits platelet activation and aggregation. This phase IV, single-arm study analyzed the safety and tolerability of ticagrelor in Taiwanese patients with non-ST-segment elevation myocardial infarction (NSTEMI) during 1 year of follow-up. METHODS: Patients aged ≥ 20 years with an index event of NSTEMI received ticagrelor (180 mg loading and 90 mg doses twice daily thereafter) plus low-dose aspirin (100 mg/day) for up to 1 year. Safety was evaluated according to adverse events (AEs), serious AEs (SAEs), and PLATO-defined bleeding events. The cumulative incidence of major cardiovascular (CV) events including CV death, myocardial infarction, and stroke was also evaluated. RESULTS: The safety population included 108 patients across 13 centers in Taiwan. During treatment, 32 (29.6%) patients had ≥ one PLATO-defined bleeding event. Major bleeding events occurred in seven (6.5%) patients with a Kaplan-Meier (KM) estimated event risk [95% confidence interval (CI)] of 7.1% (3.4%-14.4%), including life-threatening bleeding [four (3.7%) patients] and other major bleeding [three (2.8%) patients]. No PLATO-defined fatal bleeding was observed. SAEs were reported in 23 (21.3%) patients. Six (5.6%) patients experienced major CV events during the 1-year follow-up period, with a KM-estimated event risk (95% CI) of 5.6% (2.6%-12.0%). CONCLUSIONS: Ticagrelor for up to 1 year was associated with a low rate of major bleeding events and a low incidence of major CV events in Taiwanese patients with NSTEMI. The overall safety of ticagrelor was in accordance with the known safety profile of ticagrelor.

Ticagrelor in Patients with Stable Coronary Disease and Diabetes.

BACKGROUND: Patients with stable coronary artery disease and diabetes mellitus who have not had a myocardial infarction or stroke are at high risk for cardiovascular events. Whether adding ticagrelor to aspirin improves outcomes in this population is unclear. METHODS: In this randomized, double-blind trial, we assigned patients who were 50 years of age or older and who had stable coronary artery disease and type 2 diabetes mellitus to receive either ticagrelor plus aspirin or placebo plus aspirin. Patients with previous myocardial infarction or stroke were excluded. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke. The primary safety outcome was major bleeding as defined by the Thrombolysis in Myocardial Infarction (TIMI) criteria. RESULTS: A total of 19,220 patients underwent randomization. The median follow-up was 39.9 months. Permanent treatment discontinuation was more frequent with ticagrelor than placebo (34.5% vs. 25.4%). The incidence of ischemic cardiovascular events (the primary efficacy outcome) was lower in the ticagrelor group than in the placebo group (7.7% vs. 8.5%; hazard ratio, 0.90; 95% confidence interval [CI], 0.81 to 0.99; P = 0.04), whereas the incidence of TIMI major bleeding was higher (2.2% vs. 1.0%; hazard ratio, 2.32; 95% CI, 1.82 to 2.94; P<0.001), as was the incidence of intracranial hemorrhage (0.7% vs. 0.5%; hazard ratio, 1.71; 95% CI, 1.18 to 2.48; P = 0.005). There was no significant difference in the incidence of fatal bleeding (0.2% vs. 0.1%; hazard ratio, 1.90; 95% CI, 0.87 to 4.15; P = 0.11). The incidence of an exploratory composite outcome of irreversible harm (death from any cause, myocardial infarction, stroke, fatal bleeding, or intracranial hemorrhage) was similar in the ticagrelor group and the placebo group (10.1% vs. 10.8%; hazard ratio, 0.93; 95% CI, 0.86 to 1.02). CONCLUSIONS: In patients with stable coronary artery disease and diabetes without a history of myocardial infarction or stroke, those who received ticagrelor plus aspirin had a lower incidence of ischemic cardiovascular events but a higher incidence of major bleeding than those who received placebo plus aspirin. (Funded by AstraZeneca; THEMIS ClinicalTrials.gov number, NCT01991795.).

Ticagrelor in patients with diabetes and stable coronary artery disease with a history of previous percutaneous coronary intervention (THEMIS-PCI): a phase 3, placebo-controlled, randomised trial.

BACKGROUND: Patients with stable coronary artery disease and diabetes with previous percutaneous coronary intervention (PCI), particularly those with previous stenting, are at high risk of ischaemic events. These patients are generally treated with aspirin. In this trial, we aimed to investigate if these patients would benefit from treatment with aspirin plus ticagrelor. METHODS: The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS) was a phase 3 randomised, double-blinded, placebo-controlled trial, done in 1315 sites in 42 countries. Patients were eligible if 50 years or older, with type 2 diabetes, receiving anti-hyperglycaemic drugs for at least 6 months, with stable coronary artery disease, and one of three other mutually non-exclusive criteria: a history of previous PCI or of coronary artery bypass grafting, or documentation of angiographic stenosis of 50% or more in at least one coronary artery. Eligible patients were randomly assigned (1:1) to either ticagrelor or placebo, by use of an interactive voice-response or web-response system. The THEMIS-PCI trial comprised a prespecified subgroup of patients with previous PCI. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke (measured in the intention-to-treat population). FINDINGS: Between Feb 17, 2014, and May 24, 2016, 11 154 patients (58% of the overall THEMIS trial) with a history of previous PCI were enrolled in the THEMIS-PCI trial. Median follow-up was 3·3 years (IQR 2·8-3·8). In the previous PCI group, fewer patients receiving ticagrelor had a primary efficacy outcome event than in the placebo group (404 [7·3%] of 5558 vs 480 [8·6%] of 5596; HR 0·85 [95% CI 0·74-0·97], p=0·013). The same effect was not observed in patients without PCI (p=0·76, pinteraction=0·16). The proportion of patients with cardiovascular death was similar in both treatment groups (174 [3·1%] with ticagrelor vs 183 (3·3%) with placebo; HR 0·96 [95% CI 0·78-1·18], p=0·68), as well as all-cause death (282 [5·1%] vs 323 [5·8%]; 0·88 [0·75-1·03], p=0·11). TIMI major bleeding occurred in 111 (2·0%) of 5536 patients receiving ticagrelor and 62 (1·1%) of 5564 patients receiving placebo (HR 2·03 [95% CI 1·48-2·76], p<0·0001), and fatal bleeding in 6 (0·1%) of 5536 patients with ticagrelor and 6 (0·1%) of 5564 with placebo (1·13 [0·36-3·50], p=0·83). Intracranial haemorrhage occurred in 33 (0·6%) and 31 (0·6%) patients (1·21 [0·74-1·97], p=0·45). Ticagrelor improved net clinical benefit: 519/5558 (9·3%) versus 617/5596 (11·0%), HR=0·85, 95% CI 0·75-0·95, p=0·005, in contrast to patients without PCI where it did not, pinteraction=0·012. Benefit was present irrespective of time from most recent PCI. INTERPRETATION: In patients with diabetes, stable coronary artery disease, and previous PCI, ticagrelor added to aspirin reduced cardiovascular death, myocardial infarction, and stroke, although with increased major bleeding. In that large, easily identified population, ticagrelor provided a favourable net clinical benefit (more than in patients without history of PCI). This effect shows that long-term therapy with ticagrelor in addition to aspirin should be considered in patients with diabetes and a history of PCI who have tolerated antiplatelet therapy, have high ischaemic risk, and low bleeding risk. FUNDING: AstraZeneca.

Rationale, design and baseline characteristics of the effect of ticagrelor on health outcomes in diabetes mellitus patients Intervention study.

In the setting of prior myocardial infarction, the oral antiplatelet ticagrelor added to aspirin reduced the risk of recurrent ischemic events, especially, in those with diabetes mellitus. Patients with stable coronary disease and diabetes are also at elevated risk and might benefit from dual antiplatelet therapy. The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS, NCT01991795) is a Phase 3b randomized, double-blinded, placebo-controlled trial of ticagrelor vs placebo, on top of low dose aspirin. Patients ≥50 years with type 2 diabetes receiving anti-diabetic medications for at least 6 months with stable coronary artery disease as determined by a history of previous percutaneous coronary intervention, bypass grafting, or angiographic stenosis of ≥50% of at least one coronary artery were enrolled. Patients with known prior myocardial infarction (MI) or stroke were excluded. The primary efficacy endpoint is a composite of cardiovascular death, myocardial infarction, or stroke. The primary safety endpoint is Thrombolysis in Myocardial Infarction major bleeding. A total of 19 220 patients worldwide have been randomized and at least 1385 adjudicated primary efficacy endpoint events are expected to be available for analysis, with an expected average follow-up of 40 months (maximum 58 months). Most of the exposure is on a 60 mg twice daily dose, as the dose was lowered from 90 mg twice daily partway into the study. The results may revise the boundaries of efficacy for dual antiplatelet therapy and whether it has a role outside acute coronary syndromes, prior myocardial infarction, or percutaneous coronary intervention.

Profibrinolytic effect of the epigenetic modifier valproic acid in man.

AIMS: The aim of the study was to test if pharmacological intervention by valproic acid (VPA) treatment can modulate the fibrinolytic system in man, by means of increased acute release capacity of tissue plasminogen activator (t-PA) as well as an altered t-PA/Plasminogen activator inhibitor -1 (PAI-1) balance. Recent data from in vitro research demonstrate that the fibrinolytic system is epigenetically regulated mainly by histone deacetylase (HDAC) inhibitors. HDAC inhibitors, including VPA markedly upregulate t-PA gene expression in vitro. METHODS AND RESULTS: The trial had a cross-over design where healthy men (n = 10), were treated with VPA (Ergenyl Retard) 500 mg depot tablets twice daily for 2 weeks. Capacity for stimulated t-PA release was assessed in the perfused-forearm model using intra-brachial Substance P infusion and venous occlusion plethysmography. Each subject was investigated twice, untreated and after VPA treatment, with 5 weeks wash-out in-between. VPA treatment resulted in considerably decreased levels of circulating PAI-1 antigen from 22.2 (4.6) to 10.8 (2.1) ng/ml (p<0.05). It slightly decreased the levels of circulating venous t-PA antigen (p<0.05), and the t-PA:PAI-1 antigen ratio increased (p<0.01). Substance P infusion resulted in an increase in forearm blood flow (FBF) on both occasions (p<0.0001 for both). The acute t-PA release in response to Substance P was not affected by VPA (p = ns). CONCLUSION: Valproic acid treatment lowers plasma PAI-1 antigen levels and changes the fibrinolytic balance measured as t-PA/PAI-1 ratio in a profibrinolytic direction. This may in part explain the reduction in incidence of myocardial infarctions by VPA treatment observed in recent pharmacoepidemiological studies. TRIAL REGISTRATION: The EU Clinical Trials Register 2009-011723-31.

Does the timing of treatment with intra-aortic balloon counterpulsation in cardiogenic shock due to ST-elevation myocardial infarction affect survival?

BACKGROUND: Intra-aortic balloon pump (IABP) counterpulsation and primary percutaneous coronary intervention (PCI) are standard treatment modalities in cardiogenic shock (CS) complicating acute myocardial infarction. The aim of this study was to investigate the impact of the timing of IABP treatment start in relation to PCI procedure. METHODS: Data were obtained from the SCAAR registry (Swedish Coronary Angiography and Angioplasty Registry) about 139 consecutive patients with CS due to ST-elevation myocardial infarction (STEMI) who received IABP treatment. The patients were hospitalized at Sahlgrenska University Hospital, Gothenburg, during 2004-2008. The cohort was divided into the two groups: group (A) in whom IABP treatment started before start of PCI (n = 72) and group (B) in whom IABP treatment started after PCI treatment (n = 67). The primary endpoint was 30-day mortality. Propensity score (PS) adjusted Cox proportional hazards regression was used to analyze predictors of 30-day mortality. RESULTS: Mean age was 66.5 ± 12 and 28% were women. All patients have received IABP treatment 30 min before or 30 min after primary PCI. 63% had diabetes and 28% had hypertension. 16% were active tobacco smokers. The mortality rate at 30 days was 38%. IABP treatment commenced before or after PCI was not an independent predictor of mortality (P = 0.72). CONCLUSION: In this non-randomized trial the treatment with insertion of IABP before primary PCI in patients with CS due to STEMI is not associated with a more favorable outcome as compared with IABP started after primary PCI.

The impaired fibrinolytic capacity in hypertension is unaffected by acute blood pressure lowering.

The endogenous fibrinolytic system and the ability of the endothelium to release tissue-plasminogen activator (t-PA) play a pivotal role to protect humans from atherothrombotic events. We have recently reported that the decreased capacity for t-PA release in hypertension is restored with chronic blood pressure lowering. Thus, we explored if acute blood pressure lowering has the same effect. The capacity for acute t-PA release was investigated in the perfused-forearm model during stimulation by intra-arterial substance P 8 pmol/min in hypertensive subjects. The procedure was then repeated during acute blood pressure lowering (n = 9) induced by sodium nitroprusside (SNP) infusion or during placebo infusion (n = 3). SNP lowered mean arterial pressure from 108.6 (2.6) to 83.0 (2.6) (mean and SEM) mmHg (P < 0.001). Substance P induced significant increase in t-PA release during both high- and low-pressure conditions (P < 0.01, ANOVA). Peak t-PA release rate was 199 (77) and 167 (41) (mean and SEM) ng/min/l tissue, and accumulated t-PA release was 2,395 (750) and 2,394 (473) ng, during high- and low-pressure conditions, respectively. t-PA release and hemodynamic responses were almost identical during high- and low-pressure conditions (P = ns, for all). Acute blood pressure lowering does not restore stimulated t-PA release from the endothelium in hypertensive subjects. These findings are in contrast to previously described effects of chronic blood pressure treatment. Although data need to be confirmed in a larger study, they suggest that high blood pressure decreases the cellular t-PA pool rather than interferes with release mechanisms of the protein.

Impaired capacity for stimulated fibrinolysis in primary hypertension is restored by antihypertensive therapy.

The increased risk for myocardial infarction and ischemic stroke in primary hypertension suggests that the condition is associated with prothrombotic mechanisms. We have shown that patients with hypertension have an impaired capacity for acute endothelial tissue-type plasminogen activator (t-PA) release, an important local protective response to prevent formation of intravascular thrombi. The aim of the present study was to investigate whether this impairment could be restored by the lowering of blood pressure. The capacity for acute t-PA release in response to intraarterial infusion of substance P at 8 pmol/min was investigated in a perfused-forearm study in 20 hypertensive patients (12 men and 8 women). Studies were performed when patients were untreated and after 8 weeks of randomized treatment with lisinopril or felodipine that lowered blood pressure by 26/10 and 24/12 mm Hg, respectively. The t-PA release response increased significantly with treatment (ANOVA, P=0.0001), with a similar effect in the 2 treatment groups. The peak release of t-PA increased from 257 (58) to 445 (77) ng/min x L/tissue(-1) (t test, P=0.02). Also, treatment shortened the average time to peak secretion from 6.7 (1.4) to 2.7 (0.3) min (t test, P=0.01). In 6 patients with a delayed secretory peak (9 minutes or later), treatment normalized the response (chi2 test, P=0.008). Antihypertensive therapy restores the capacity for acute t-PA release and improves the rapidity of the response in patients with primary hypertension. Similar responses with the 2 regimens suggest that the improvement is related to the blood pressure reduction as such. This effect may contribute to the thromboprotective effect of antihypertensive treatment.

Prolonged cyclic strain impairs the fibrinolytic system in cultured vascular endothelial cells.

OBJECTIVE: We previously reported that patients with primary hypertension have an impaired ability to release tissue-type plasminogen activator acutely from the vascular endothelium, and recently found that lowering blood pressure can restore this capacity. We hypothesized that the suppression of the fibrinolytic system is caused by the chronic pressure-induced increased haemodynamic load on the endothelium. DESIGN AND METHODS: This study investigated the effect of the tensile force component of blood pressure by exposing cultured human aortic endothelial cells to 10% cyclic strain for 6-72 h. Messenger RNA levels of tissue-type plasminogen activator, urokinase-type plasminogen activator, and plasminogen activator inhibitor 1 were analysed using Taqman real-time reverse transcriptase-polymerase chain reaction and protein release by enzyme-linked immunosorbent assay. RESULTS: Tensile stimulation resulted in a transient initial upregulation of tissue-type plasminogen activator mRNA at 6 h (53%), which declined with time, and at 48 h had switched to a 28% downregulation. The reduction was sustained after 72 h. Tissue-type plasminogen activator protein secretion showed a similar but somewhat delayed response, with a transient increase in release at 6 h (60%), declining to a final 12% reduction at 72 h. A similar pattern was observed for urokinase-type plasminogen activator mRNA. By contrast, plasminogen activator inhibitor 1 mRNA expression and protein secretion increased at all timepoints (16-47%). CONCLUSION: Prolonged tensile stimulation impairs fibrinolytic activity in human aortic endothelial cells by a dual action, with suppression of plasminogen activator expression and increased inhibitor production. This effect of tensile stress may contribute to the reduced fibrinolytic capacity observed in patients with hypertension.