Effect of high dose verapamil on restenosis after peripheral angioplasty

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta-adrenoreceptor blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-adrenoreceptor blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD. This is the second update of a Cochrane review first published in 2003.

OBJECTIVES

To determine the effects of anti-hypertensive drugs in patients with both raised blood pressure and symptomatic PAD in terms of the rate of cardiovascular events and death, symptoms of claudication and critical leg ischaemia, and progression of atherosclerotic PAD as measured by ankle brachial index (ABI) changes and the need for revascularisation (reconstructive surgery or angioplasty) or amputation.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched March 2013) and CENTRAL (2013, Issue 2).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least one anti-hypertensive treatment against placebo or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author (DAL) and checked by the other (GYHL). Potentially eligible studies were excluded when the results presentation prevented adequate extraction of data and enquiries to authors did not yield raw data.

MAIN RESULTS

Eight RCTs were included with a total of 3610 PAD patients. Four studies compared a recognised class of anti-hypertensive treatment with placebo and four studies compared two anti-hypertensive treatments with each other. Studies were not pooled due to the variation of the comparisons and the outcomes presented. Overall the quality of the available evidence was unclear, primarily as a result of a lack of detail in the study reports on the randomisation and blinding procedures and incomplete outcome data. Two studies compared angiotensin converting enzyme (ACE) inhibitors against placebo. In one study there was a significant reduction in the number of cardiovascular events in patients receiving ramipril (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58 to 0.91; n = 1725). In the second trial using perindopril (n = 52) there was a marginal increase in claudication distance but no change in ABI and a reduction in maximum walking distance. A trial comparing the calcium antagonist verapamil versus placebo in patients undergoing angioplasty (n = 96) suggested that verapamil reduced restenosis (per cent diameter stenosis (± SD) 48.0% ± 11.5 versus 69.6% ± 12.2; P < 0.01), although this was not reflected in the maintenance of a high ABI (0.76 ± 0.10 versus 0.72 ± 0.08 for verapamil versus placebo). Another study (n = 80) demonstrated no significant difference in arterial intima-media thickness (IMT) in men receiving the thiazide diuretic hydrochlorothiazide (HCTZ) compared to those receiving the alpha-adrenoreceptor blocker doxazosin (-0.12 ± 0.14 mm and -0.08 ± 0.13 mm, respectively; P = 0.66). A study (n = 36) comparing telmisartan to placebo found a significant improvement in maximum walking distance at 12 months with telmisartan (median (interquartile range (IQR)) 191 m (157 to 226) versus 103 m (76 to 164); P < 0.001) but no differences in ABI (median (IQR) 0.60 (0.60 to 0.77) versus 0.52 (0.48 to 0.67)) or arterial IMT (median (IQR) 0.08 cm (0.07 to 0.09) versus 0.09 cm (0.08 to 0.10)). Two studies compared the beta-adrenoreceptor blocker nebivolol with either the thiazide diuretic HCTZ or with metoprolol. Both studies found no significant differences in intermittent or absolute claudication distance, ABI, or all-cause mortality between the anti-hypertensives. A subgroup analysis of PAD patients (n = 2699) in a study which compared a calcium antagonist-based strategy (verapamil slow release (SR) ± trandolapril) to a beta-adrenoreceptor blocker-based strategy (atenolol ± hydrochlorothiazide) found no significant differences in the composite endpoints of death, non-fatal myocardial infarction or non-fatal stroke with or without revascularisation (OR 0.90, 95% CI 0.76 to 1.07 and OR 0.96, 95% CI 0.82 to 1.13, respectively).

AUTHORS' CONCLUSIONS

Evidence on the use of various anti-hypertensive drugs in people with PAD is poor so that it is unknown whether significant benefits or risks accrue. However, lack of data specifically examining outcomes in PAD patients should not detract from the overwhelming evidence on the benefit of treating hypertension and lowering blood pressure.

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta-blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD. This is an update of a Cochrane review first published in 2003.

OBJECTIVES

To determine the effects of anti-hypertensive drugs on cardiovascular events and death, symptoms of claudication, critical leg ischaemia, progression of PAD and revascularisation or amputation in people with hypertension and PAD SEARCH STRATEGY: The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched May 2009) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 2). The authors studied abstracts of cardiology meetings.

SELECTION CRITERIA

Randomised controlled trials of at least one anti-hypertensive treatment against placebo, or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author (DAL) and checked by the other (GYHL). Eligible studies were excluded when results presentation prevented adequate extraction of data and enquiries to authors did not yield raw data.

MAIN RESULTS

Four studies were included. Two compared ACE inhibitors against placebo. In the HOPE study there was a significant reduction in the number of cardiovascular events in 168 patients receiving ramipril (OR 0.72, 95% confidence interval 0.58 to 0.91). In the second trial using perindopril in a small numbers of patients, there was a marginal increase in claudication distance but no change in ankle brachial pressure index (ABPI) and a reduction in maximum walking distance.The third trial in patients undergoing angioplasty suggested that the calcium antagonist verapamil reduced restenosis, although this was not reflected in the maintenance of a high ABPI. Another small study demonstrated no significant difference in arterial intima-media thickness with men receiving the thiazide diuretic hydrochlorathiazide compared to those receiving the alpha-adrenoreceptor blocker doxazosin.

AUTHORS' CONCLUSIONS

Evidence on various anti-hypertensive drugs in people with PAD is poor so that it is unknown whether significant benefits or risks accrue from their use. Lack of data specifically examining outcomes in PAD patients should not detract from the compelling evidence of the benefit of treating hypertension and lowering blood pressure.

Comparison of Selective AT1-Receptor Blockade Versus ACE Inhibition for Restenosis Prophylaxis in Patients With Peripheral Occlusive Arterial Disease After Stent Angioplasty: A Randomized, Controlled, Proof-of-Concept Study

Different components of the renin-angiotensin system (RAS) have been demonstrated in atherosclerotic plaques. However, the involvement of the RAS in the complex process of in-stent restenosis is not yet clear. In this prospective, randomized, double-blind, controlled proof-of-concept study, we compared the 2 different pharmacological approaches, selective AT1-receptor-blockade with candesartan vs ACE inhibition with quinapril to reduce in-stent restenosis after stent angioplasty of the superficial femoral artery. Twenty-two hypertensive patients with stage IIb peripheral occlusive arterial disease and severe claudication who had been successfully treated with percutaneous transluminal angioplasty (PTA) and stent implantation were randomly assigned to receive daily doses of either candesartan (32 mg) or quinapril (20 mg). Primary end point was restenosis 6 months after intervention, assessed by angiography. Secondary end points were pain-free walking distance, determined by treadmill ergometry; determination of crurobrachial indices; and intima-media thickness (IMT). At 6 months, the rate of restenosis on angiography was 34% in the candesartan group and 71% in the quinapril group (P = .043). Relevant restenosis was found in 3 patients (27%) in the candesartan group and in 7 patients (64%) in the quinapril group. Patients in the candesartan group were able to walk farther on a treadmill (increase: 135 m ± 20 m) compared with patients in the quinapril group (increase: 83 m ± 21 m). The IMT at the stent edge was not significantly different in the 2 groups (candesartan: 1.9 mm ± 0.5 mm; quinapril: 2.0 mm ± 0.3 mm). This study revealed significant benefit of a pharmacological restenosis regimen using the AT1-receptor antagonist candesartan in patients with severe atherosclerosis after superficial femoral artery stenting compared with treatment with the ACE inhibitor quinapril. Further prospective studies in patients are required to confirm these results.

Candesartan Treatment for Peripheral Occlusive Arterial Disease after Stent Angioplasty

OBJECTIVES

In this prospective, double-blind, placebo-controlled study we observed the influence of treatment with candesartan 8mg on restenosis rates after stent implantation into the femoral artery 6 months after percutaneous transluminal angioplasty (PTA). We hypothesised that angiotensin II type 1 (AT1)-receptor blockade with candesartan would reduce restenosis rates by reducing angiotensin II-mediated intima hyperproliferation within the stented vessel segment in patients with peripheral occlusive disease.

PATIENTS AND METHODS

Eighty-seven patients with peripheral occlusive arterial disease stage IIb who had been successfully treated with PTA and stent implantation were randomised to receive orally either candesartan 8mg (n = 44) or placebo (n = 43). Follow-up included evaluation of the degree of stenosis and thickness of the intima-media complex (primary endpoint). In addition, thickness of the interventricular septum, crurobrachial pressure ratios, and pain-free walking distance were determined (secondary endpoints).

RESULTS

The degree of stenosis after 6 months was not significantly different between the groups studied (35.9 +/- 39.6% for candesartan vs 36.0 +/- 38.4% for placebo). Relevant restenosis including stent occlusions was found in nine patients (20.5%) in the candesartan group and in ten patients (23.3%) in the placebo group. The thickness of the intima-media complex 6 months after stent implantation was 1.60 +/- 0.32mm in the candesartan group and 1.64 +/- 0.32mm in the placebo group (not significant). There were no differences in secondary endpoints between the treatment groups. Controls after 3 months (20.9 +/- 33.6% for candesartan vs 27.6 +/- 38.3% for placebo; p = 0.39) and 9 months (44.1 +/- 40.8% for candesartan vs 47.7 +/- 37.2% for placebo; p = 0.67) of therapy revealed a lower degree of stenosis in patients treated with candesartan.

CONCLUSIONS

Although not significant, candesartan treatment tended to improve the prognostic benefits after stent implantation, suggesting that an antiproliferative effect after stenting may need higher doses than an antihypertensive effect of the drug. This hypothesis requires confirmation in further prospective studies with higher daily doses of candesartan, which are already in progress.

Periprocedural routines of coronary angioplasty--extreme diversity with unrevealed consequences

Our objective was to evaluate the current trends of coronary angioplasty periprocedural care in the state of Israel. PTCA technology has undergone through some major developments and refinements, which have yielded new algorithms and routines. With this shift of paradigms, some of the periprocedural routines (these include medications and dosing before, during and after the procedure, as well as the handling of anti-coagulation, femoral sheath removal and the extent of patient monitoring post-PTCA) have been partially re-established. In order to assess trends in periprocedural care, we elected to analyze the current state of practice in the state of Israel. A questionnaire was sent to every cardiac catheterization laboratory in Israel that performs PTCA. An authorized senior cardiologist representing the laboratory submitted the information required for our survey. A nurse-to-nurse telephone questionnaire was conducted simultaneously to cross-examine the validity of the data. All centers submitted results. The average heparin dose for PTCA varied between 5000 and 15 000 units, ACT was monitored routinely by some and not at all by others, post-PTCA heparin administration was routinely administered by some institutions and not by others, and the mean femoral sheath dwell time ranged from 4 to 18 h. Post-PTCA cardiac monitoring varied from 6 to more than 24 h. Some institutions prescribed to all patients nitrates, calcium channel blockers and low-molecular-weight heparin, while others did not. We conclude that there is profound variability in the periprocedural routines that may translate into a significant cost increase, patient discomfort, a prolonged monitoring and hospital stay, and potential patient morbidity. We suggest that these routines should be critically evaluated, and that if they do not contribute to the procedural success and patient well-being they should be abandoned.

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Therefore, treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD.

OBJECTIVES

To determine the effects of anti-hypertensive drugs on the: cardiovascular events and death in patients with hypertension and PAD; symptoms of claudication and critical leg ischaemia; progression of PAD, and revascularisation, or amputations.

SEARCH STRATEGY

Trials were sought via the Specialised Register of the Cochrane Peripheral Vascular Diseases Group (last searched July 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 2, 2003), and the NHS Database of Abstracts of Reviews of Effectiveness (DARE) (last searched August 2002). There were no language restrictions. Abstracts of cardiology meetings were studied. Reference lists of papers were also examined.

SELECTION CRITERIA

Randomised controlled trials of at least one anti-hypertensive treatment against placebo, or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD. Trials of poor quality and execution were excluded, as were cross-over trials.

DATA COLLECTION AND ANALYSIS

Data were extracted by one reviewer and checked by the other. Eligible studies were excluded when presentation prevented adequate extraction of data, and enquiries to authors did not yield the raw data.

MAIN RESULTS

Two studies were included in the review. In one trial using perindopril in small numbers of patients with PAD, there was a marginal increase in claudication distance (weighted mean difference (WMD) 8.0, 95% confidence interval (CI) -30.66 to 46.66), but no change in ankle brachial pressure index (ABPI), (WMD 0, 95% CI -0.14 to 0.14), and a reduction in walking distance (WMD -46, 95 % CI -169.24 to 77.24). In patients undergoing angioplasty, a second trial suggested that the calcium antagonist verapamil reduced restenosis, although this was not reflected in the maintenance of a high ABPI.

REVIEWER'S CONCLUSIONS

The evidence for various anti-hypertensive drug classes in PAD is poor, so that it is unknown whether significant benefit or risk accrues from their use. In view of this, no definite recommendations on use or avoidance can be made from the available data.

Potential use of a low-molecular-weight heparin to prevent restenosis in patients with extensive wall damage following peripheral angioplasty

The long-term outcome of primary successful percutaneous transluminal angioplasty (PTA) for patients with peripheral occlusive arterial disease (POAD) is frequently compromised by the development of restenosis, especially when extensive dissections result from the angioplastic procedure. Unfortunately, prevention of the occlusive process by means of drugs such as antithrombotics, anticoagulants, thrombolytics, corticosteroids, lipid reducers, or cytostatics has not been demonstrated convincingly. The authors sought to clarify whether such patients could benefit from the postsurgical administration of low-molecular-weight heparin. A total of 172 POAD patients with extensive dissections after PTA in the pelvic or upper leg regions were randomized for 7-day post-PTA intravenous treatment with either full heparinization or nadroparin calcium followed by adjunctive oral aspirin for 6 months. The primary outcome measure was the degree of stenosis (normal findings; stenosis < 50%, > 50%, > 80%, occlusion) before and after angioplasty, as well as 3 weeks and 3 and 6 months after dilation; secondary efficacy criteria included changes in the Fontaine stage and in the crurobrachial ratio. No significant treatment-related differences were found at the 3 post-PTA follow-up examinations with regard to the degree of stenosis. This was also the case for the subgroup of patients (n = 62) who had undergone angioplasty in the pelvic region. By contrast, when angioplasty was performed in the superficial femoral artery (n = 110), the degree of restenosis was significantly lower (p<0.01) among patients receiving nadroparin calcium compared to those given heparin at week 3, month 3, and month 6. No intergroup differences emerged for secondary outcome measures in the long term or for safety parameters. These preliminary results indicate that patients with extensive dissections after PTA treatment for POAD in the upper leg region might benefit from a reduction in the rate of restenosis by administration of 7-day weight-adjusted nadroparin calcium.

Effects of probucol on rat carotid artery responses to balloon catheter injury

Balloon catheter injury to the rat common carotid artery has been widely used for testing potential therapies for post-angioplasty restenosis. However, the model has become somewhat discredited because a number of drugs that inhibit intimal thickening, measured 14 days after balloon catheter injury, have been found to be ineffective in clinical trials. Probucol has recently been shown to reduce the incidence of post-angioplasty restenosis in a number of small clinical trials, making it possible to reassess the validity of the rat balloon injury model. The effects of probucol on the underlying causes of intimal thickening in balloon-injured rat carotid arteries were quantified. Probucol inhibited medial smooth muscle cell proliferation by 23% on day 4 after injury (P=0.009), and by 65% on day 10 after injury (P=0.026). Smooth muscle cell migration was reduced by 64% (P=0.008) in probucol-treated animals. In marked contrast, intimal smooth muscle cell proliferation was significantly increased by 41% (P=0.024) by probucol. There was no significant effect on intimal thickening or smooth muscle cell death. These data suggest that drugs that inhibit both medial smooth muscle cell proliferation and migration in the rat balloon injury model may prove useful in the treatment of post-angioplasty restenosis.

Current status of safety and efficacy of calcium channel blockers in cardiovascular diseases: a critical analysis based on 100 studies

Recently, serious concerns have been expressed about the long-term safety of the calcium channel blockers (CCBs) as a group. Safety and efficacy are, however, ultimately linked to each other; therefore both must be evaluated especially in the therapy of angina and hypertension, the main clinical indications for CCBs. The structural, functional, and pharmacokinetic heterogeneity of CCBs means that the efficacy and dangers of one subclass, such as the short-acting dihydropyridines (DHPs), in one situation, such as unstable angina, do not necessarily apply in other clinical situations. One hundred studies are reviewed according to their methods of data collection: case series, case control, cohort, randomized controlled trials (RCTs), and meta-analyses. Large, well-designed RCTs and the meta-analyses based on these trials remain the gold standard. Observational studies, though potentially less reliable sources of information because of selection bias, may nevertheless produce hypotheses that must then be tested in RCTs. Regarding safety, both observational studies and RCTs suggest that adverse effects of CCBs may be linked to short-acting agents, specifically short-acting nifedipine. Two good studies favor the safety of verapamil, even in short-acting form. Incomplete but increasing overall evidence favors the safety of longer-acting DHPs. Heart failure remains a class contraindication to the use of all CCBs, with some exceptions. Regarding efficacy, there are positive results of RCTs with CCBs in 2 specific clinical situations, namely, verapamil in postinfarct protection in the absence of pre-existing heart failure, and 2 outcome studies on hypertension with longer acting DHPs. These results cannot automatically be applied to other clinical situations and to other CCBs. For example, there is no evidence for the safety or efficacy of DHPs used without beta blockers in postinfarct patients. In diabetic hypertensives, 2 relatively large RCTs show that the blood pressure can be reduced by DHP-based therapy in diabetics, with a reduction in hard end points. To achieve current blood pressure goals, combination therapy is almost always necessary, and in diabetics there is strong evidence that 1 essential component should be an angiotensin converting enzyme inhibitor. The future aim with CCBs must be to obtain a large database gathered from RCTs, which will give the same certainty about efficacy and safety that already holds for use of the diuretics in hypertension, beta-blockers in postmyocardial infarction patients, and the angiotensin converting enzyme inhibitors in heart failure.