Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients

Isolated Systolic Hypertension in the Elderly

Isolated systolic hypertension (ISH) is the predominant form of hypertension in persons older than 50 years, who represent the majority of individuals with hypertension. Systolic blood pressure (SBP) determines Joint National Committee blood pressure stage, and therefore the need for therapy, far more often than diastolic blood pressure (DBP). SBP consistently is associated with greater risk for overall mortality, coronary heart disease, stroke, congestive heart failure, renal failure, and other end points. In addition, clinicians are far less aggressive and less successful at controlling SBP compared with DBP. Thus, SBP should be acknowledged as the major criterion that determines diagnosis, staging, and therapeutic management in older individuals. Several recent large, randomized, placebo-controlled trials of drug therapy targeting ISH in the elderly have shown dramatic reductions in cardiovascular end points and mortality. The treatment of patients with ISH must occur within the framework of the larger goals associated with treatment of hypertension generally. Lifestyle modification, including salt restriction and increasing physical activity, may contribute to improvements in arterial compliance and control of ISH in particular. In clinical trials, most antihypertensive agents decrease SBP more than DBP. However, certain drug classes, such as angiotensin-converting enzyme inhibitors and nitrates, have advantageous properties that may make them particularly useful for the treatment of ISH.

Vasopeptidase inhibition: effective blood pressure control for vascular protection

Angiotensin converting enzyme (ACE) inhibition is a well-established principle in the treatment of hypertension, and numerous large scale clinical studies have clearly demonstrated the beneficial effects of inhibiting the renin-angiotensin-aldosterone system (RAS) in hypertension. The clinical success of ACE inhibitors encouraged attempts to inhibit other key enzymes in the regulation of vascular tone, such as the neutral endopeptidase (NEP). Similar to ACE, NEP is an endothelial cell surface metalloproteinase, which is involved in the degradation of several regulatory peptides including the natriuretic peptides, and augments vasodilatation and natriuresis through increased levels of atrial natriuretic peptide. By inhibiting the RAS and potentiating the natriuretic peptide system at the same time, combined NEP/ACE inhibitors, the so-called "vasopeptidase inhibitors," reduce vasoconstriction and enhance vasodilatation, and in turn decrease peripheral vascular resistance and blood pressure. Within the vessel wall this may lead to a reduction of vasoconstrictor and proliferative mediators such as angiotensin II and endothelin-1, and may increase local levels of bradykinin as well as natriuretic peptides. Based on these considerations, numerous preclinical studies with vasopeptidase inhibitors have been performed and reveal promising results in experimental hypertension. Correspondingly, large-scale clinical studies in patients with hypertension are on the way, to transfer the principle of vasopeptidase inhibition from bench to bedside.

Management After Myocardial Infarction

Individuals who survive an acute myocardial infarction (MI) have up to a ninefold greater risk of cardiovascular morbidity and mortality compared with the general population. The modification of traditional coronary risk factors, including hypertension, hyperlipidemia, tobacco use, and diabetes mellitus, constitutes one of the cornerstones of management after acute MI. Therapies aimed at reversing the pathophysiologic disorders that lead to endothelial dysfunction, thrombosis, and atherosclerotic plaque instability may improve the prognosis for patients after acute MI. Aggressive risk stratification diagnostic testing can identify patients at the highest risk for adverse events. Prior to hospital discharge, patients should have an evaluation of left ventricular systolic function, an assessment for the risk for residual myocardial ischemia, and a clinical assessment of the risk for serious ventricular arrhythmias. An array of pharmaceutical agents is available for the secondary prevention of MI, including antiplatelet agents, beta-blockers, angiotensin-converting enzyme inhibitors, and statins.

ST-Segment Elevation Myocardial Infarction

ST-segment elevation myocardial infarction (MI) is an emergency medical condition. Expediting the steps leading to coronary reperfusion is of critical importance in improving survival after acute MI. After the diagnosis of acute MI is made, patients should be treated with oxygen, aspirin, nitroglycerin, beta-blockers, heparin, and analgesics, barring any contraindications. If an experienced cardiac catheterization laboratory is available within 60 to 90 minutes, then catheter-based reperfusion therapy is recommended; otherwise, thrombolysis should be considered as an alternate therapy. Therapy with a reduced-dose thrombolytic agent and a glycoprotein IIb/IIIa receptor inhibitor appears to be of an added benefit in establishing TIMI (Thrombolysis in Myocardial Infarction) 3 flow, but this approach awaits final approval prior to widespread use. The adjunctive use of glycoprotein IIb/IIIa receptor inhibitors with percutaneous transluminal coronary angioplasty, with or without stenting, appears to be beneficial and is being used more frequently in the acute setting. Coronary angiography should be performed in patients who fail to respond to thrombolytic therapy or who have evidence of recurrent ischemia. This procedure should not be routinely performed in patients who have responded to thrombolytic therapy. Four to 6 days after an acute MI event, assessment of left ventricular function is recommended. Submaximal exercise test (with or without nuclear or echocardiographic imaging) should be considered in patients prior to discharge from the hospital--an exception can be made in patients with one-vessel disease treated successfully with percutaneous transluminal coronary angioplasty. After discharge, a regular exercise test should be obtained 4 to 6 weeks after an uncomplicated acute MI event. Secondary prevention measures such as weight loss, cessation of smoking, aspirin, beta-blockers, lipid-lowering agents, and angiotensin-converting enzyme inhibitors should be considered in all patients, barring contraindications.

Diabetes mellitus and cardiovascular disease

Diabetes is associated with a high incidence and poor prognosis of cardiovascular disease, and with high short- and long-term mortality. Adequate treatment of cardiovascular disorders and aggressive management of coexisting risk factors have proved to be at least as effective in diabetic as in nondiabetic patients in randomized, controlled studies. Indeed, treating diabetic patients with cardiovascular disease results in a larger absolute risk reduction than in nondiabetic subjects. Nevertheless, diabetic patients often receive inadequate therapy, which may, to a certain extent, explain their poor prognosis. Recommendations for the treatment of diabetic patients with acute myocardial infarction should include beta-blockers, aspirin, and ACE-inhibitors in all patients in whom no specific contraindications exist. Fibrinolysis should be administered when indicated, and the benefits of improving glycemic control should not be forgotten either. In patients with multi-vessel disease who need revascularization, when selecting the type of procedure, the superiority of surgical revascularization over angioplasty should be borne in mind. Even heart transplantation should be included as a therapeutic option since there are no data to support the exclusion of patients on account of their diabetes. Finally, coexisting risk factors should be intensively treated through lifestyle intervention, with or without drug therapy, in order to achieve secondary prevention goals.

Management of intermittent claudication: the importance of secondary prevention

Atherosclerotic peripheral arterial disease (PAD) is a common disorder usually associated with silent or symptomatic arterial disease elsewhere in the circulation and a cluster of cardiovascular risk factors inducing atheroma progression and/or thrombotic complications. Because of these strong clinical associations, especially with coronary heart disease, the ankle-brachial pressure index (ABPI) is of prognostic significance. The clinical management of IC should include relief of symptoms combined with prevention of secondary cardiovascular complications, e.g. acute thrombotic events causing limb- or life-threatening ischaemia, which are often due to atherosclerotic plaque rupture leading to thrombotic vessel occlusion. Many patients with PAD do not receive an optimum package of secondary prevention, tailored to include maximum cholesterol reduction, BP and glycaemic control, ACE inhibition and single or combination anti-platelet therapy. This review considers recent information from large secondary prevention trials, e.g. the PAD subgroups within the HOPE, CAPRIE and statin studies. Slowing progression of atherosclerosis, and inducing stabilisation and regression of atheromatous plaques, is now feasible using long-term combination drug therapy. The phrase angle quotation mark, leftangle quotation mark, leftconservative therapyangle quotation mark, rightangle quotation mark, right, popular among vascular surgeons, implies a passive minimal-intervention strategy of surveillance and lifestyle advice; such terminology is perhaps no longer appropriate since considerable improvements in survival are likely to accrue if all patients with PAD, especially those with low ABPI, receive vigorous, titrated medical therapies, tailored to individual patients, as part of an evidence-based secondary prevention regime.

Fosinopril versus amlodipine comparative treatments study: a randomized trial to assess effects on plasminogen activator inhibitor-1

BACKGROUND

ACE inhibitors and calcium antagonists may modulate fibrinolysis. We conducted a randomized controlled trial to assess the effects of these drugs on plasminogen activator inhibitor-1 (PAI-1) antigen, an inhibitor of fibrinolysis.

METHODS AND RESULTS

Participants with hypertension and type 2 diabetes mellitus (n=96, 51% black) were randomized after an initial 4 weeks of placebo to double-blind 20 or 40 mg fosinopril or 5 or 10 mg amlodipine daily for 4 weeks in a fixed-dose regimen. After 4 weeks of placebo washout, the patients received 4 weeks of crossover treatments. After treatment with placebo, systolic and diastolic blood pressure were 143+/-2 and 86+/-1 mm Hg and plasma PAI-1 was 43.4+/-2.3 ng/mL. Amlodipine achieved a greater systolic and diastolic blood pressure reduction than fosinopril (10 mm Hg versus 8 mm Hg, P=0.029, and 5 mm Hg versus 3 mm Hg, P=0.040, respectively) but tended to increase PAI-1, whereas fosinopril tended to decrease PAI-1 (5.4+/-3.6 versus -3.8+/-2.5 ng/mL, P=0.045). The PAI-1 changes depended on drug dose (6.5+/-6.1 and 3.4+/-3.9 ng/mL with amlodipine 10 and 5 mg, respectively, and -0.4+/-3.1 and -7.4+/-4.0 ng/mL with fosinopril 20 and 40 mg, respectively, P for trend 0.024). No significant differences between fosinopril and amlodipine were found for short-term changes in tissue plasminogen activator antigen, fibrinogen, C-reactive protein, and interleukin-6. The findings were similar in black and white participants.

CONCLUSIONS

Short-term treatment with fosinopril significantly reduced PAI-1 compared with amlodipine in a dose-dependent fashion. This effect, which was independent of blood pressure reduction, may account for the improved clinical outcomes achieved with ACE inhibitors compared with calcium antagonists.

[Pathophysiology and therapeutic aspects of left ventricular "remodeling" in the post-infarct phase]

Left ventricular remodeling is the process by which ventricular size, shape, and function are regulated by mechanical, neurohormonal, and genetic factors. Remodeling may be physiological and adaptive during normal growth or pathological due to myocardial infarction, cardiomyopathy, hypertension, or valvular heart disease. Postinfarction remodeling has been divided into an early phase within 72 hours and a late phase beyond 72 hours. The early phase involves expansion of the infarct zone, which may result in early ventricular rupture or aneurysm formation. Late remodeling involves the left ventricle globally and is associated with time-dependent dilatation, the distortion of ventricular shape, and mural hypertrophy. Hypertrophy and collagen degradation are adaptive responses during postinfarction remodeling. Myocardial repair is triggered by cytokines released from injured myocytes. Ventricular remodeling is influenced most by infarct artery patency. Once infarct evolution has occurred, pharmacological intervention, like ACE inhibition and beta-adrenoreceptor blocking agents, may minimize infarct expansion and ventricular dilatation and improve the long-term prognosis.

From the HOPE to the ONTARGET and the TRANSCEND studies: challenges in improving prognosis

The Heart Outcomes Prevention Evaluation (HOPE) study conclusively demonstrated that ramipril, an angiotensin-converting enzyme (ACE) inhibitor, reduces the risk of cardiovascular death, myocardial infarction (MI), and death in patients at risk for cardiovascular events but without heart failure. The Study to Evaluate Carotid Ultrasound Changes in Patients Treated with Ramipril and Vitamin E (SECURE) substudy demonstrated that ramipril also reduced atherosclerosis. These results suggest that the renin-angiotensin system (RAS) has a more important role in the development and progression of atherosclerosis than previously believed, and they indicate the need for further clinical studies to define the range of benefits available from modifying the RAS. Achieving maximum benefit may require treatment with both an ACE inhibitor and an angiotensin II type-1 receptor blocker (ARB). The Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) study indicated that combining an ACE inhibitor with an ARB decreased blood pressure and improved the ejection fraction more than treatment with either drug alone in patients with congestive heart failure. The Valsartan in Heart Failure Trial (Val-HeFT) showed that the combination of an ACE inhibitor and an ARB reduced hospitalization for heart failure in patients with congestive heart failure by 27.5%, although no decrease in all-cause mortality was observed. The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) is a large, long-term study (23,400 patients, 5.5 years). It will compare the benefits of ACE inhibitor treatment, ARB treatment, and treatment with an ACE inhibitor and ARB together, in a study population with established coronary artery disease, stroke, peripheral vascular disease, or diabetes with end-organ damage. Patients with congestive heart failure will be excluded. In a parallel study, patients unable to tolerate an ACE inhibitor will be randomized to receive telmisartan or placebo (the Telmisartan Randomized Assessment Study in ACE-I Intolerant Patients with Cardiovascular Disease [TRANSCEND]). The primary endpoint for both trials is a composite of cardiovascular death, MI, stroke, and hospitalization for heart failure. Secondary endpoints will investigate reductions in the development of diabetes mellitus, nephropathy, dementia, and atrial fibrillation. These 2 trials are expected to provide new insights into the optimal treatment of patients at high risk of complications from atherosclerosis.

The role of the renin-angiotensin system in the development of cardiovascular disease

A direct, continuous, and independent relation between blood pressure and the incidence of various cardiovascular events, such as stroke and myocardial infarction, is now well accepted. The increase in risk can be attributed to structural and functional changes in target organs. Central to many of these pathophysiologic processes is the renin-angiotensin system (RAS), specifically, angiotensin II. Binding of angiotensin II to angiotensin II type-1 (AT(1)) receptors produces acute vasoconstriction, leading to an increase in blood pressure. AT(1) receptor activation also contributes independently to chronic disease pathology by promoting vascular growth and proliferation, and endothelial dysfunction. These negative consequences of angiotensin II are partly counteracted by angiotensin II type-2 (AT(2)) receptor stimulation, which has favorable effects on tissue growth and repair processes. Thus, the use of selective AT(1) receptor antagonists in the treatment of hypertension has a 2-fold rationale: (1) selective AT(1) receptor blockade targets the final common pathway for all major detrimental cardiovascular actions of angiotensin II, and (2) circulating angiotensin II levels (which increase during AT(1) receptor antagonist treatment) will be free to act only at unopposed AT(2) receptors, potentially providing additional end-organ protection. Angiotensin-converting enzyme (ACE) inhibitors interrupt the RAS by preventing the conversion of angiotensin I to angiotensin II. They also increase plasma levels of bradykinin, which possesses vasodilatory and tissue-protective properties. The combination of an AT(1) receptor antagonist with an ACE inhibitor represents an appealing therapeutic strategy, because it should produce more complete blockade of the RAS, while preserving the beneficial effects mediated by AT(2) receptor stimulation and increased bradykinin levels.

The 24-hour blood pressure pattern: does it have implications for morbidity and mortality?

The onset of adverse cardiovascular events demonstrates a circadian pattern that reaches a peak in the morning shortly after awakening and arising. A parallel, 24-hour cyclical pattern has also been observed in the activities of various physiologic measurements, including blood pressure, heart rate, sympathetic nervous system activity, and platelet adhesiveness. Although a direct link has not yet been established, it can be postulated that the early morning surge in blood pressure may be a factor in precipitating acute cardiovascular episodes. Similar to the early morning blood pressure surge, blood pressure variability throughout the day appears to be a further independent risk factor for hypertensive target organ damage. Thus, it is reasonable to select an antihypertensive agent that offers smooth and well-sustained blood pressure control for the full 24-hour dosing interval, including the vulnerable early morning period. The results of clinical trials using ambulatory blood pressure monitoring have shown that telmisartan, an angiotensin II receptor antagonist, possesses such properties. Whether or not these attributes of telmisartan might translate into improvements in cardiovascular morbidity and mortality will be explored in the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET). This study will compare the effects of telmisartan 80-mg monotherapy, ramipril 10-mg monotherapy, or a combination of telmisartan 80 mg plus ramipril 10 mg, on cardiovascular endpoints in patients at high risk of cardiovascular events, several of whom are likely to be hypertensive at baseline. Inclusion of the telmisartan plus ramipril treatment arm will allow investigation of the potential advantages presented by combining an angiotensin-converting enzyme inhibitor with an angiotensin II receptor antagonist.

Angiotensin II and trials of cardiovascular outcomes

Proven cardiovascular benefit from angiotensin-converting enzyme (ACE) inhibition is a cornerstone of evidence-based medicine. The first study to show dramatic benefits from ACE inhibition was the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS-I), in which a 31% decrease in the rate of death was observed in patients with severe heart failure at the end of 1 year of enalapril treatment (p = 0.001). This result led to large long-term studies-including Survival and Ventricular Enlargement (SAVE), Acute Infarction Ramipril Efficacy (AIRE), Trandolapril Cardiac Evaluation (TRACE), and Study of Left Ventricular Dysfunction (SOLVD)-which verified that ACE inhibition decreases heart failure, myocardial infarction (MI), and mortality, and that striking benefit could be observed within 30 days. Short-term studies of patients in the acute phase of a heart attack verified that ACE inhibition provided rapid benefits. A meta-analysis of short-term (up to 8 weeks) studies of ACE inhibition (including CONSENSUS-II, Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico [GISSI]-3, International Study of Infarct Survival [ISIS]-4, and the Chinese Captopril Study [CCS]-1) demonstrated that post-MI risk was reduced by 10% within the first day of treatment. The immediacy of the benefit suggested that ACE inhibition not only improved cardiovascular function in failing hearts but also affected important mechanisms in patients without overt heart failure. Effects on more general mechanisms of heart disease suggested that patients with problems other than hypertension or heart failure might benefit from ACE inhibitors. The Heart Outcomes Prevention Evaluation (HOPE) study investigated the hypothesis that ACE inhibition would confer benefits to patients who were at high risk for cardiovascular events, but who were without left ventricular dysfunction or heart failure. Long-term reductions in MI, stroke, cardiac arrest, and heart failure, as well as improvements in mortality, were observed in this population after treatment with ACE inhibitors. Substudies of the HOPE study revealed that ACE inhibition reduced progression of atherosclerosis and improved myocardial remodeling. Taken together, these studies provide evidence that supports treatment of a broad population of patients at risk for cardiovascular events with ACE inhibitors. The next step is to combine ACE inhibition with other treatments to maximize patient benefit. The Ongoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) will compare the efficacy of an ACE inhibitor (ramipril) with an angiotensin receptor blocker (telmisartan), and determine whether these treatments in combination will further reduce morbidity and mortality from cardiovascular disease.

Comparative effects of estrogen and angiotensin-converting enzyme inhibition on plasminogen activator inhibitor-1 in healthy postmenopausal women

BACKGROUND

This study compares the effect of estrogens and ACE inhibition on plasminogen activator inhibitor-1 (PAI-1) concentrations in healthy postmenopausal women, genotyped for a 4G/5G polymorphism in the PAI-1 promoter, a polymorphism shown to influence PAI-1 concentrations. Methods and Results- Morning estradiol, PAI-1, tissue plasminogen activator, plasma renin activity, angiotensin II, and aldosterone were measured in 19 postmenopausal women (5G/5G:4G/5G:4G4G=5:10:4, respectively) at baseline and during randomized, single-blind, crossover treatment with conjugated equine estrogens 0.625 mg per os per day, ramipril 10 mg per os per day, and combination estrogens and ramipril. Estradiol (P<0.005) and angiotensin II (P<0.01) were significantly higher during estrogens. Plasma renin activity was significantly increased during ACE inhibition (P<0.05). Both conjugated estrogens [PAI-1 antigen from 12.5 (7.6, 17.4) [mean (95% CI)] baseline to 6.6 (2.6, 10.7) ng/mL, P<0.01] and ACE inhibition [8.3 (4.9, 11.7) ng/mL, P<0.005] decreased PAI-1 without decreasing tissue plasminogen activator. The effect of combined therapy on PAI-1 [5.6 (2.3, 8.8) ng/mL] was significantly greater than that of ramipril alone (P<0.05). There was a significant effect of PAI-1 4G/5G genotype on baseline PAI-1 concentrations (P=0.001) and a significant interactive effect of 4G/5G genotype and treatment, such that genotype influenced the change in PAI-1 during ramipril (P=0.011) or combined therapy (P=0.006) but not during estrogens (P=0.715).

CONCLUSIONS

ACE inhibition with ramipril and conjugated estrogens similarly decrease PAI-1 antigen concentrations in postmenopausal women. Larger studies that use clinical outcomes are needed to determine whether PAI-1 4G/5G genotype should influence the choice of conjugated estrogens or ACE inhibition for the treatment of healthy postmenopausal women.

The prevalence of treatable left ventricular systolic dysfunction in patients who present with noncardiac vascular episodes: a case-control study

OBJECTIVES

We sought to determine the prevalence of treatable left ventricular (LV) systolic dysfunction (LVSD) in patients who present with their first noncardiac vascular episode.

BACKGROUND

Screening for LV dysfunction in patients who present with their first stroke (cerebrovascular accident), their first transient ischemic attack (TIA) or their first manifestation of peripheral vascular disease (PVD) may represent a golden opportunity to identify treatable LV dysfunction, and so their known high incidence of sudden cardiac death may be reduced.

METHODS

Participating in this study were 522 (75%) of 700 consecutive patients (302 patients with stroke, TIA or PVD and 220 age- and gender-matched control subjects). Each underwent a full clinical assessment, 12-lead electrocardiography and two-dimensional echocardiography. Left ventricular dysfunction was defined as LV ejection fraction < or = 40%.

RESULTS

Seventy-two (28%) patients with vascular disease and 11 (5.5%) control subjects were found to have LVSD. Twenty-six (28%) stroke patients, 22 (26%) patients with TIA and 24 (31%) patients with PVD had LVSD. Left ventricular systolic dysfunction was symptomatic in 44% of patients and in 35% of control subjects.

CONCLUSIONS

Left ventricular systolic dysfunction is five times more common among patients with stroke, TIA and PVD than among age- and gender-matched control subjects. Asymptomatic LVSD is more common than symptomatic LVSD in these patients. These findings suggest that routine screening of all patients with noncardiac vascular episodes for LVSD should now be considered. Future studies should investigate whether identifying and treating LVSD in these patients would reduce their known high rate of cardiac death.

Evidence-based evaluation of calcium channel blockers for hypertension: equality of mortality and cardiovascular risk relative to conventional therapy

OBJECTIVES; We present a meta-analysis based on three recent, substantial, randomized outcome trials and several smaller trials that compared calcium channel blockers (CCBs) with conventional therapy (diuretics or beta-blockers) or with angiotensin-converting enzyme (ACE) inhibitors.

BACKGROUND

There is continuing uncertainty about the safety and efficacy of CCBs in the treatment of hypertension. Previous meta-analyses conflict and suggest that CCBs increase myocardial infarction (MI) or protect from stroke.

METHODS

Standard procedures for meta-analysis were used to analyze three major trials on 21,611 patients and another three lesser studies to a total of 24,322 patients.

RESULTS

Calcium channel blockers have a strikingly similar risk of total and cardiovascular mortality and of major cardiovascular events to conventional therapy. Calcium channel blockers give a lower risk of nonfatal stroke (-25%, p = 0.001) and a higher risk of total MI (18%, p = 0.013), chiefly nonfatal (18%). After performing the Bonferroni correction for multiplicity, these p values become 0.004 and 0.052, respectively. When compared with ACE inhibitors in 1,318 diabetic patients, CCBs had a substantially higher risk of nonfatal (relative risk [RR] = 2.259) and total MI (RR = 2.204, confidence interval 1.501 to 3.238; p = 0.001 or 0.004 with Bonferroni correction). Total and cardiovascular mortality rates are similar. To confirm the hypothesis that ACE inhibitors are superior to CCBs in diabetic patients requires more trial data, especially with renal end points.

CONCLUSIONS

Mortality (total and cardiovascular) and major cardiovascular events with CCBs were apparently similar to those events seen with conventional first-line therapy (diuretics or beta-blockers). Stroke reduction more than balanced increased MI. In diabetics, CCBs may be less safe than ACE inhibitors.

Destabilization of AT(1) receptor mRNA by calreticulin

AT(1) receptor activation leads to vasoconstriction, blood pressure increase, free radical release, and cell growth. AT(1) receptor regulation contributes to the adaptation of the renin-angiotensin system to long-term stimulation and serves as explanation for the involvement of the AT(1) receptor in the pathogenesis of cardiovascular disease. The molecular mechanisms involved in AT(1) receptor regulation are poorly understood. Here, we report that angiotensin II accelerates AT(1) receptor mRNA decay in vascular smooth muscle cells. A cognate mRNA region within the 3' untranslated region at bases 2175 to 2195 governs the inducible decay of the AT(1) receptor mRNA. Sequential protein purifications led to the discovery of a novel mRNA binding protein, calreticulin, which mediates destabilization of the AT(1) receptor mRNA. Angiotensin II-caused phosphorylation of calreticulin enables binding of calreticulin to the AT(1) receptor mRNA at bases 2175 to 2195 and propagates calreticulin-induced acceleration of AT(1) receptor mRNA decay. Thus, a novel mRNA binding protein, calreticulin, is discovered, which causes AT(1) receptor mRNA degradation via binding to a distinct mRNA region in the 3' untranslated region. These findings display a novel mechanism of posttranscriptional mRNA processing.

Hypertension and diabetes: the scope of the problem

Cardiovascular and renal diseases in diabetes stem from an accelerated form of atherosclerosis in both small and large blood vessels. Diabetic nephropathy is a clinical hallmark of microangiopathy and often leads to end-stage renal failure. Significantly, microalbuminuria is an independent predictor of cardiovascular morbidity and mortality in both the diabetic and non-diabetic population. In diabetic patients, it is also strongly associated with proliferative retinopathy, neuropathy and hypertension. Effective blood pressure reduction in patients with type 2 diabetes and diabetic nephropathy is known to reduce albuminuria, delay the progression of diabetic nephropathy, postpone renal failure and improve survival. These benefits have been demonstrated with a variety of blood pressure-lowering agents, including beta-blockers, calcium channel blockers, diuretics and angiotensin-converting enzyme (ACE) inhibitors. Less is known about the renal effects of the newest class of antihypertensive agents, the angiotensin II receptor antagonists (AIIRAs). Irbesartan is an AIIRA that provides antihypertensive efficacy comparable to ACE inhibitors but with superior tolerability. The PRogram for Irbesartan Mortality and morbidity Evaluations (PRIME) is an important morbidity and mortality program encompassing the Irbesartan Diabetic Nephropathy Trial (IDNT) and the IRbesartan MicroAlbuminuria type 2 diabetes mellitus in hypertensive patients (IRMA II) study. PRIME is evaluating the effects of irbesartan in preventing diabetic nephropathy and end-stage renal failure and in reducing cardiovascular events in high-risk hypertensive patients with type 2 diabetes. The trials were completed at the end of 2000.

Characteristics of 15,314 hypertensive patients at high coronary risk. The VALUE trial. The Valsartan Antihypertensive Long-term Use Evaluation

Valsartan is an orally active, selective antagonist of the angiotensin II-1 (AT1) receptor developed for the treatment of hypertension. The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) Trial of Cardiovascular Events in Hypertension is a double-blind, randomized prospective, parallel group study designed to compare the effects of valsartan with those of the calcium-antagonist amlodipine on the reduction of cardiac morbidity and mortality. Patients with essential hypertension, aged 50 years and older, and at particularly high risk of coronary events were enrolled. 18,119 patients were screened and 15,314 patients in 31 countries were randomized mainly between January 1998 and December 1999. These hypertensives had a mean blood pressure of 154.7/87.5 mmHg at the time of their randomization to blinded medication. The population comprises both genders (men 57.6%), Caucasians (89.1%), mean age 67.2 years, mean body mass index 28.6 kg/m2, coronary heart disease (45.8%), high cholesterol (33.0%), type 2 diabetes mellitus (31.7%) and smokers (24.0%). More than 92% of the randomized participants had been treated for high blood pressure for at least 6 months when screened for the study. The randomized population is now being treated (goal blood pressure < 140/90 mmHg) in adherence with the protocol until at least 1450 patients experience primary cardiac endpoint defined as clinically evident or aborted myocardial infarction, hospitalization for heart failure or death caused by coronary heart disease.

Economics of antihypertensive therapy in the elderly

Because of the high incidence of morbidity and mortality associated with hypertension in the elderly, the treatment of hypertension in this patient group must involve consideration of clinical, humanistic and economic outcomes. The most frequently used method of pharmacoeconomic analysis for antihypertensive therapy involves cost-effectiveness analysis, although several other methods are available. Current evidence reveals a trend toward cost effectiveness of antihypertensive treatment in elderly patients. However, these formal analyses are limited by the need for extrapolation of data regarding efficacy and level of risk from epidemiological and randomised trials, information which is often lacking. To incorporate economic factors into clinical decision making, other measures of economic impact should be explored. The economic impact of antihypertensive therapy is affected by the level of risk for the patient and the efficacy of the treatment. Data indicate that the risk of morbidity and mortality related to hypertension increases with age and that current antihypertensive drugs reduce this risk. When choosing an antihypertensive agent, the following parameters should be considered: acquisition cost, likelihood of adverse effects and other determinants of treatment adherence, and individual predictors of response. The economic outcomes will be maximised if prudent drug selection is supplemented by appropriate diagnostic and classification procedures and reduction of cardiovascular risk factors other than hypertension. The accumulation of data addressing the risks and benefits of therapy for the very old and the comparative efficacy of newer antihypertensive therapies will further clarify the decision-making process.

Long-term treatment with perindopril ameliorates dobutamine-induced myocardial ischemia in patients with coronary artery disease

The present study was designed to examine whether long-term blockade of angiotensin-converting enzyme (ACE) with perindopril ameliorates dobutamine-induced myocardial ischemia in patients with coronary artery disease (CAD). Twelve patients with proven CAD were randomly divided in two groups; one group received perindopril (8 mg/day, p.o.) for 3 months and another group served as a control. To evaluate anti-ischemic effects of perindopril, dobutamine stress echocardiography was performed before and 3 months after the treatment in a double-blind manner. Long-term treatment with perindopril significantly ameliorated the dobutamine-induced myocardial ischemia, as evaluated by time to the onset of symptoms, magnitude of electrocardiographic ST-segment changes, and left ventricular wall motion score (all P<0.05). The treatment significantly decreased serum ACE activities (P<0.01) and increased plasma bradykinin concentrations (P<0.05). The extent of reduction of left ventricular wall motion score by perindopril was closely correlated with that of inhibition of serum ACE activities (P<0.01) and with that of increase in plasma bradykinin concentrations (P<0.05). By contrast, no such beneficial changes were noted in the control group. These results provide the first evidence that long-term treatment with perindopril exerts anti-ischemic effects on the myocardial ischemia induced by increased myocardial oxygen demand in patients with CAD.

Long-term renal consequences of hypertension for normal and diseased kidneys

Substantial evidence indicates that the adverse effects of hypertension on the kidney depend on the degree to which systemic blood pressure elevations are transmitted to the renal microvasculature. Such blood pressure transmission and consequent susceptibility to hypertensive renal damage is markedly exacerbated in states characterized by preglomerular vasodilation and an impairment of the normally protective renal autoregulatory mechanisms, e.g. diabetes or chronic renal disease. Moreover, this pathophysiology gives rise to the prediction that prevention of hypertension-induced barotrauma will require blood pressure to be reduced well into the normotensive range in such patients, as is being recognized in the currently recommended blood pressure goals. Agents that block the renin-angiotensin system should be preferred as initial therapy as they may provide additional risk reductions and minimize the potassium and magnesium depletion associated with the diuretic use usually necessary to achieve the lower blood pressure targets. The current failure to achieve optimal blood pressure reductions may be contributing not only to the still escalating incidence of end-stage renal disease in diabetic patients, but also to their greatly increased cardiovascular morbidity and mortality.

Highlights of latest American College of Cardiology and American Heart Association Guidelines for Management of Patients with Acute Myocardial Infarction

The recently published American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Acute Myocardial Infarction stress 3 major points: (1) the prehospital phase from the onset of symptoms to definitive therapy in the emergency department must be shortened by 50% in order to reduce further the estimated 30% mortality rate for all patients in the community who suffer an acute myocardial infarction; (2) a more widespread use of thrombolytic agents is warranted because of the demonstrated, extremely time-dependent benefit to survivorship: the sooner it is given, the better the outcome; and (3) the administration of aspirin (160-325 mg) daily for an indefinite period is perhaps the most important therapy for a patient with acute myocardial infarction. Long-term therapy with lipid-lowering Statin drugs and angiotensin-converting enzyme inhibitor agents are gaining increasing evidence-based data to support their perpetual use as well.

Effects of captopril and omapatrilat on early post-myocardial infarction survival and cardiac hemodynamics in rats: interaction with cardiac cytokine expression

The purpose of this study was to evaluate and compare the effects of simultaneous angiotensin-converting enzyme (ACE) and neutral endopeptidase 24.11 (NEP) inhibition by the vasopeptidase inhibitor omapatrilat (10 and 40 mg x kg(-1) x day(-1)) with those of the selective ACE inhibitor captopril (160 mg x kg(-1) x day(-1)) on survival, cardiac hemodynamics, and cytokine mRNA expression in left ventricular (LV) tissues 4 days after myocardial infarction (MI) in rats. The effects of the co-administration of both B1 and B2 kinin receptor antagonists (2.5 mg x kg(-1) x day(-1) each) with and without omapatrilat were also evaluated to assess the role of bradykinin (BK) during this post-MI period. Both omapatrilat and captopril treatments improve early (4 days) post-MI survival when started 4 h post-MI. The use of kinin receptor antagonists had no significant effect on survival in untreated MI rats and omapatrilat-treated MI rats. This improvement in survival with omapatrilat and captopril is accompanied by a reduced LV end-diastolic pressure (LVEDP) and pulmonary congestion. The use of kinin receptor antagonists had little effect on cardiac hemodynamics or morphologic measurements. Acute MI significantly increased the expression of cardiac cytokines (TNF-alpha, TGF-beta1, and IL-10). Captopril significantly attenuated this activation, while omapatrilat had variable effects: sometimes increasing but generally not changing activation depending on the cytokine measured and the dose of omapatrilat used. The co-administration of both kinin receptor antagonists attenuates the increase in expression of cardiac TNF-alpha and TGF-beta1 after omapatrilat treatment. Taken together, these results would suggest that despite very marked differences in the way these drugs modified the expression of cardiac cytokines, both omapatrilat and captopril improved early (4 days) post-MI survival and cardiac function to a similar extent.

From pharmacogenomics to improved patient outcomes: angiotensin I-converting enzyme as an example

Here we report the utility of a molecular epidemiologic approach for common, polygenic diseases. Since 1992, the angiotensin I-converting enzyme (ACE) deletion/deletion (D/D) genotype has been linked to several cardiovascular diseases, including diabetic nephropathy. Earlier, the ACE D/D genotype had been associated with excess tissue ACE activity. We have observed an association of the ACE D/D genotype with a large number of common diseases, including chronic renal failure due to non-insulin-dependent diabetes mellitus or hypertension, hypertensive peripheral vascular disease, and emphysema [chronic obstructive pulmonary disease (COPD)]. ACE inhibitors have been in clinical use since 1977 and have a well-known safety record. Armed with the knowledge that ACE overactivity was associated with their disease, we gave what was intended to be a tissue ACE-inhibitory dose of a hydrophobic ACE inhibitor to 800 Caucasian and African-American male patients with hypertension and 200 Caucasian and African-American male patients with chronic renal failure, over a period of 3 years. We here report their outcomes, which include those of two patients with end-stage hypertensive peripheral vascular disease and one patient with end-stage emphysema (COPD). As a group, the outcomes are superior to what is available in the literature. This experience suggests the power of pharmacogenomics to improve clinical outcomes for common diseases safely, quickly, and inexpensively, if effective drugs already exist.

Cardiovascular medications taken by patients aged >or=70 years hospitalized for acute coronary syndromes before hospitalization and at hospital discharge

A prospective study was performed in 177 patients, mean age 78+/-6 years, hospitalized with acute coronary syndromes. Obstructive coronary artery disease was documented by coronary angiography in 154 of 177 patients (87%). Coronary revascularization was performed in 96 of 177 patients (54%). Five of 177 patients (3%) died during hospitalization. Compared to use before hospitalization, at hospital discharge the use of aspirin increased from 43% to 84% (p<0.001), the use of clopidogrel increased from 21% to 54% (p<0.001), the use of beta blockers increased from 38% to 76% (p<0.001), the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers increased from 42% to 70% (p<0.001), the use of long-acting nitrates increased from 15% to 31% (p<0.001), and the use of calcium channel blockers decreased from 28% to 23% (p=NS). Dyslipidemia was present in 62% of the 177 patients. The use of statins increased from 34% before hospitalization to 63% at hospital discharge (p<0.001).

Intermittent claudication: pharmacoeconomic and quality-of-life aspects of treatment

The purpose of this article is to review the literature on the pharmacoeconomics of treatment for intermittent claudication and to discuss the importance of quality-of-life assessment for evaluating treatment strategies. Systemic risk reduction is the primary objective in the treatment of patients with intermittent claudication, as these patients have a high future risk of cardiovascular morbidity and mortality. Modification of cardiovascular risk factors accompanied by antiplatelet therapy is likely to improve overall survival, reduce myocardial infarction and stroke, and will, perhaps, also reduce the risk of ulcers and amputation at acceptable cost-effectiveness ratios. The second goal in the treatment of patients with intermittent claudication is to improve their walking capacity and community-based functional status. Supervised exercise training is the most effective noninvasive intervention to improve walking capacity, but may have elevated indirect costs. Among patients with disabling claudication who are candidates for invasive therapeutic procedures, angioplasty is cost effective in those with femoropopliteal stenosis or occlusion and in those with critical limb ischaemia and a stenosis. For all these therapeutic strategies there is a need to relate the costs to a relevant and comprehensive measure of effectiveness. Quality-of-life evaluation by using questionnaires exploring the specific problems encountered by patients with intermittent claudication in their daily life appear to be the most appropriate tool to evaluate the net result of a treatment. Cost-utility studies by combining pecuniary and quality-of-life evaluations provide information that is extremely useful to patients with intermittent claudication, regulatory authorities, the pharmaceutical industry and healthcare providers.

Cardiovascular risk in patients with early renal insufficiency: implications for the use of ACE inhibitors

Patients with end-stage renal disease die from cardiovascular disease at a much younger age than people in the general population do. Here, we review the evidence linking early renal insufficiency (ERI) to an increased cardiovascular risk. A number of cardiovascular risk factors become prevalent with ERI, including night-time hypertension, increase in serum levels of lipoprotein (a), homocysteine and asymmetric dimethyl-arginine, and insulin resistance. Also, an epidemiologic association between coronary artery disease (CAD) and nephrosclerosis, a frequent cause of ERI in the elderly, is documented. In the middle-aged, general population ERI, found in 8% of women and 9% of men, was not associated with cardiovascular disease. However, in a representative sample of middle-aged British men the risk of stroke was 60% higher for the subgroup of individuals with ERI. In people at high cardiovascular risk (mostly CAD), the Heart Outcomes Prevention Evaluation (HOPE) study found a 2-fold (unadjusted) or 1.4-fold (adjusted) higher incidence of cardiovascular outcomes with ERI. The incidence of primary outcome increased with the level of serum creatinine. At least four studies have determined the cardiovascular risk associated with ERI in hypertension. In Hypertension Detection and Follow-up Program, as in HOPE, cardiovascular mortality increased with higher serum creatinine levels (5-fold difference in cardiovascular mortality between the lowest and the highest creatinine strata). In patients with hypertension with low risk, the Hypertension Optimal Treatment and a small Italian trial found about a doubling in cardiovascular outcomes in ERI. However, in the Multiple Risk Factor Intervention Trial, not baseline serum creatinine level, but its increase on follow-up predicted future cardiovascular disease. These observational data suggest that ERI, independent of etiology, is a strong predictor of cardiovascular disease, present in 10% of a population at low, and up to 30% at high, cardiovascular risk. No prospective therapeutic trials aimed at reducing the cardiovascular burden in individuals with ERI are available. Subgroup analyses of the HOPE study indicate that ACE inhibition with ramipril is beneficial without an increased risk of adverse effects like acute renal failure or hyperkalemia. Thus the frequent practice of withholding ACE inhibitors from patients with mild renal insufficiency is unwarranted, especially since this identifies a group at high risk who appears to benefit most from treatment. In addition, there is evidence that ACE inhibitors improve renal outcomes in renal insufficiency. Prospective studies should test the predictive power of ERI for cardiovascular disease and therapeutic options.

The use of ranolazine in cardiovascular disease

Ranolazine is a novel drug that has shown promise in the treatment of cardiovascular disease. Ranolazine exerts its effect by shifting myocardial energy metabolism away from free fatty acids and toward glucose as the substrate for production of adenosine triphosphate. Preclinical data have confirmed that ranolazine reduces myocardial ischaemic injury in various animal models. Researchers are continuing to gather clinical data but findings to date support the conclusion that ranolazine has anti-ischaemic effects without inducing the typical reduction in blood pressure and heart rate associated with the use of traditional anti-ischaemic agents. Given the absence of haemodynamic effects associated with ranolazine, it has great promise as a drug that could be added to existing therapy without concern for hypotensive or bradycardic side effects. Ranolazine has been shown to improve exercise-induced myocardial ischaemia and to lessen the severity of angina in the setting of chronic ischaemic heart disease. Early preclinical observations also suggest positive effects of ranolazine in the management of congestive heart failure; however, trials in this area are ongoing. Several recently completed Phase III clinical studies in patients with chronic ischaemic heart disease have confirmed the findings of smaller trials and should satisfy regulatory concerns necessary to place ranolazine on the commercial market in the US. The maker of ranolazine, CV Therapeutics (Palo Alto, California), will file a New Drug Application (NDA) with the US FDA for the approval of ranolazine as an anti-anginal in the near future.

Congestive heart failure: what should be the initial therapy and why?

Left ventricular systolic dysfunction is associated with neurohormonal activation which contributes to progressive ventricular remodeling and worsening clinical heart failure. Renin-angiotensin-aldosterone and sympathetic nervous systems are activated, not only in patients with clinically overt heart failure, but also in patients with asymptomatic or minimally symptomatic left ventricular systolic dysfunction. Activation of the angiotensin and adrenergic systems produces deleterious effects on systemic and coronary hemodynamics, promotes myocyte hypertrophy and fibroblast growth, and myocyte necrosis and apoptosis. Thus, therapy of heart failure should consist of pharmacologic agents not only to relieve symptoms but also to prevent and attenuate ventricular remodeling and progressive heart failure, thereby improving prognosis. In patients who are symptomatic, ACE inhibitors along with digitalis and diuretics as initial therapy (triple therapy) have the greater potential to improve exercise tolerance and decrease the incidence of treatment failure compared with diuretics alone or a combination of diuretics and digitalis. Diuretics alone should not be considered for long-term therapy as plasma renin activity, angiotensin II, aldosterone, norepinephrine and vasopressin levels may increase. ACE inhibitors decrease mortality in patients with heart failure resulting from left ventricular systolic dysfunction. The results of presently available studies indicate that angiotensin II receptor blockers (ARBs) do not provide any advantage over ACE inhibitors regarding survival benefit but may be better tolerated. Long-term adrenergic inhibition with the use of ss-adrenoceptor antagonists added to ACE inhibitors is associated with attenuation of ventricular remodeling, improvement in ventricular function and clinical class and survival of patients with symptomatic systolic left ventricular failure. Thus, initial pharmacotherapy for systolic heart failure should consist of: maximal tolerated dosages of ACE inhibitors;ARBs if ACE inhibitors are not tolerated because of intractable cough or angioedema;adequate dosages of hydralazine and isosorbide dinitrate if ACE inhibitors or ARBs are not tolerated; relatively low dosages of digoxin (serum concentrations of < or = 1.0 ng/dl) if not contraindicated; and diuretics to relieve congestive symptoms. Addition of spironolactone to ACE inhibitors can result in a significant reduction in the risk of sudden death in patients with symptomatic severe heart failure. Myocardial infarction resulting from ischemic heart disease is the most common cause of systolic left ventricular failure and the therapeutic modalities with potential to reduce the risks of myocardial infraction, such as risk factor modification, adequate control of diabetes and hypertension, antiplatelet agents and lipid-lowering agents, should also be included in the initial therapy.

Blood pressure as a surrogate end point for hypertension

OBJECTIVE

To review relevant literature and provide opinions regarding the use of blood pressure as a surrogate measure to predict cardiovascular risk.

DATA SOURCES

Primary and review articles were identified by MEDLINE search (1990-January 2001) and through secondary sources.

STUDY SELECTION AND DATA EXTRACTION

Studies and review articles that related to the interpretation of blood pressure as a surrogate measure were reviewed. Information that was relevant to this topic was included.

DATA SYNTHESIS

The measurement of blood pressure is subject to numerous sources of error and bias. Patients who perform home blood pressure testing and self-report these values frequently leave out high values and add ghost values into logbooks. Additionally, analysis of recent data suggests that at any given level of blood pressure that is achieved, cardiovascular risk reduction may not be the same with different therapeutic agents. It is also now recommended that systolic blood pressure be used in preference to diastolic blood pressure to determine risk and to assess management strategies. Although 24-hour blood pressure measurements may be the best predictors of cardiovascular risk, this has not been demonstrated in a long-term morbidity trial.

CONCLUSIONS

Blood pressure is a relatively poor surrogate measure. Unfortunately, no alternatives are available at this time. Therefore, every attempt must be made to accurately determine blood pressure and to assess risk and benefit from specific antihypertensive agents. Systolic blood pressure should be the predominant blood pressure measure used to evaluate patients, especially middle-aged and elderly individuals.

Reducing the risk of stroke in diabetes: what have we learned that is new?

Given the significant public health impact of stroke and the identification of nonmodifiable (age, gender, race/ethnicity) and modifiable (blood pressure, diabetes, lipid profile, and lifestyle) risk factors, early prevention strategies should be initiated. When a patient suffers a stroke, the focus of care becomes prevention of future events. For the patient with diabetes, comprehensive medical management of ischaemic stroke (primary or secondary prevention) includes antihypertensive and lipid-lowering therapy, as well as antiplatelet therapy. Despite the cerebrovascular risk reduction with these modalities, clearly new agents are needed. The Heart Outcomes Prevention Evaluation (HOPE) study provides compelling evidence that treatment with the angiotensin converting enzyme inhibitor, ramipril, can further reduce the risk of stroke in high-risk patients by mechanisms other than lowering blood pressure. In HOPE, patients were normotensive at baseline. Therefore, for the first time, in a patient population without left ventricular dysfunction, the effects of an ACE inhibitor ramipril on reducing stroke risk were demonstrated. Ramipril 10 mg achieved a significant 33% reduction in stroke among patients with diabetes. Based on the HOPE study, the recently published American Heart Association guidelines for the primary prevention of stroke recommend ramipril to prevent stroke in high-risk patients and in patients with diabetes and hypertension. Wide-scale adherence to these guideline recommendations for the prevention of primary and secondary stroke would significantly benefit the public health.

Clinical trial evidence for cardiovascular risk reduction in type 2 diabetes

Major clinical trials have shown that excellent glycemic control, sustained over time, can prevent or delay the microvascular complications of diabetes, including retinopathy, nephropathy, and neuropathy. No prospective trial has clearly shown that glycemic intervention can prevent the macrovascular complications of diabetes, such as myocardial infarction, cerebrovascular accident, and amputation. However, a number of landmark clinical trials have shown the efficacy of control of blood pressure and lipids and use of antiplatelet agents (mainly aspirin) in protecting the macrovasculature of individuals with diabetes. In this article, glycemic, blood pressure, lipid, and antiplatelet trials relevant to the treatment of people with type 2 diabetes are reviewed.

Treatment of hypertension in the elderly

Hypertension is a common condition among older people in most developed countries, and is a very important, if not the most important, risk factor for all subtypes of vascular disease and death. Many clinical trials in older people have demonstrated significant reductions in myocardial infarctions and strokes when antihypertensive drugs are provided. Lifestyle modifications are still recommended because they can lower a surrogate end point--blood pressure--but there are no data showing they reduce event rates. It is not appropriate to limit the choice of initial drug for hypertensive older individuals to a single class of agents, since so many older people have other medical problems that affect this decision. Monotherapy with an alpha blocker, however, is no longer recommended, even for men with hypertension and benign prostatic hypertrophy, as doxazosin was associated with a higher rate of cardiovascular events in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial. The classic strategy of an initial diuretic (for at least 1 month) will likely be verified by the final results of ongoing randomized trials, expected in 2003. Until then, this strategy is effective, inexpensive, and unlikely to cause many adverse effects. Probably the most important exhortation, however, should be to achieve the blood pressure goal appropriate for the patient's risk status. Numerous clinical trials in older hypertensive patients have shown that more benefits accrue when the goal blood pressure is achieved than if a specific antihypertensive agent is chosen as initial therapy. Future cardiovascular risk may be related directly to the blood pressure attained, rather than to how it was attained.

Effect of crossing over hypertensive patients from a beta-blocker to an angiotensin receptor antagonist on resistance artery structure and on endothelial function

BACKGROUND

Treatment of essential hypertensive patients with an AT1 angiotensin receptor antagonist has previously resulted in correction of resistance artery structure and endothelial function, whereas in a parallel group treated with the beta-blocker atenolol there was no improvement of altered vascular structure and function. To test the hypothesis that patients previously treated with atenolol could present improvement of vascular structure and endothelial function if they were subjected to blockade of the renin-angiotensin system, we crossed over hypertensive patients that had been randomized to treatment with the beta-blocker atenolol to treatment with the AT1 antagonist irbesartan, and studied small artery structure and endothelial function before and after treatment.

METHODS

Eleven essential hypertensive patients (51 +/- 2 years, range 38-65; 75% male) that had previously been randomized to treatment with atenolol and treated for 1 year with good blood pressure control, were crossed over to treatment with the AT1 antagonist irbesartan for 1 year. Small resistance arteries were dissected from gluteal subcutaneous biopsies that were performed before and after 1 year of treatment. The structure and endothelial function of the resistance arteries were studied on a pressurized myograph.

RESULTS

Blood pressure control (129 +/- 3.3/85 +/- 1.8 mmHg) was identical to that achieved previously with atenolol (131 +/- 3.3/84 +/- 1.1 mmHg). Following 1 year of treatment, the arterial media width to lumen ratio (M/L) of resistance arteries (lumen diameter, 150-350 microm), which had remained unchanged under atenolol treatment, decreased from 8.44 +/- 0.45% when patients were on atenolol, to 6.46 +/- 0.30%, P < 0.01, when patients received irbesartan. Maximal acetylcholine-induced endothelium-dependent relaxation was 81.1 +/- 4.1% when patients were on atenolol, unchanged from before starting treatment with the beta-blocker, and was normalized by irbesartan (to 94.8 +/- 2.0%, P < 0.01).

CONCLUSION

Crossing over essential hypertensive patients with well-controlled blood pressure from the beta-blocker atenolol to the AT1 receptor antagonist irbesartan resulted in correction of previously persistently altered vascular structure and endothelial function, suggesting a structural and endothelial vascular protective effect of antihypertensive treatment with the AT1 receptor antagonist.

What is the place of beta-blockade in patients who have experienced a myocardial infarction with preserved left ventricular function? Evidence and (mis)interpretation

Beta blockers have long been used in patients who have experienced a myocardial infarction. However, many new therapies are available for this patient group, and as a result, the current role of beta blockers may have become uncertain. In this article we address a series of questions related to the important and continuing role of beta blockade after myocardial infarction.

Autonomic tone as a cardiovascular risk factor: the dangers of chronic fight or flight

Chronic imbalance of the autonomic nervous system is a prevalent and potent risk factor for adverse cardiovascular events, including mortality. Although not widely recognized by clinicians, this risk factor is easily assessed by measures such as resting and peak exercise heart rate, heart rate recovery after exercise, and heart rate variability. Any factor that leads to inappropriate activation of the sympathetic nervous system can be expected to have an adverse effect on these measures and thus on patient outcomes, while any factor that augments vagal tone tends to improve outcomes. Insulin resistance, sympathomimetic medications, and negative psychosocial factors all have the potential to affect autonomic function adversely and thus cardiovascular prognosis. Congestive heart failure and hypertension also provide important lessons about the adverse effects of sympathetic predominance, as well as illustrate the benefits of beta-blockers and angiotensin-converting enzyme inhibitors, 2 classes of drugs that reduce adrenergic tone. Other interventions, such as exercise, improve cardiovascular outcomes partially by increasing vagal activity and attenuating sympathetic hyperactivity.

Is aspirin "the weakest link" in cardiovascular prophylaxis? The surprising lack of evidence supporting the use of aspirin for cardiovascular disease

It is currently fashionable to prescribe aspirin, long-term to people with or at high risk of vascular events due to atherosclerosis. There is a moderately conclusive evidence for a short-term benefit after an acute vascular event. However, there is remarkably little evidence that long-term aspirin is effective for the prevention of vascular events and managing side effects may be expensive. Reductions in nonfatal vascular events may reflect an ability of aspirin to alter cosmetically the presentation of disease without exerting real benefit. Cardiovascular medicine appears prone to fads and fashions that are poorly substantiated by evidence. The current fashion for prescribing aspirin is reminiscent of the now discredited practice of widespread prescription of class I anti-arrhythmic drugs for ventricular ectopics. We should learn from experience.

What should the role of ACE inhibitors be in the treatment of diabetes? Lessons from HOPE and MICRO-HOPE

Experimental and clinical evidence suggest that angiotensin converting enzyme (ACE) inhibition may reduce cardiovascular (CV) risk by directly affecting endothelial dysfunction, atherosclerosis and thrombus formation. These direct effects are in addition to effects on vascular tone or pressure. The Health Outcomes and Prevention Evaluation (HOPE) study assessed the role of an ACE inhibitor ramipril in reducing CV events in 9297 patients > or = 55 years who were at high risk of CV events but did not have left ventricular dysfunction, heart failure, or high blood pressure at the time of study entry. In the overall HOPE population, the risk of the primary composite outcome (cardiovascular death, myocardial infarction, or stroke) was reduced by 22% (p < 0.001), and in patients with diabetes plus one other CV risk, it was reduced by 25% (p = 0.0004). Ramipril treatment achieved risk reduction in patients with mild renal insufficiency (serum creatinine > or = 1.4 mg/dl). Ramipril treatment did not increase adverse events in patients with renal insufficiency. The Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and Vitamin E (SECURE) demonstrated that ramipril 10 mg significantly reduced the rate of carotid intimal medial thickening, suggesting a direct effect on atherosclerotic progression.