Insertion-deletion polymorphism of the ACE gene modulates reversibility of endothelial dysfunction with ACE inhibition

A case control association study of ACE gene polymorphism (I/D) with hypertension in Punjabi population from Faisalabad, Pakistan

Angiotensin converting enzyme (ACE) is a key component of renin angiotensin aldosterone system. It converts angiotensin I to angiotensin II. Insertion/deletion (I/D) polymorphism of ACE gene is found associated with several complications. However, its association with hypertension and related metabolic diseases is still controversial. So, the aim of the present study was to check this association for Punjabi population from Faisalabad, Pakistan. For this purpose, blood samples (patients = 100, controls = 48) were collected and several biochemical parameters were measured. Genotyping for ACE (I/D) polymorphism was performed by polymerase chain reaction (PCR) assay. ID genotype is found prevalent in the studied population as 41% in control subjects and 61% in patients. Furthermore, chi-square analysis showed significant (p = 0.005) difference for genotypic frequencies between both groups. One-way ANOVA for association of II, ID, and DD genotypes with anthropometric, clinical, and biochemical parameters showed that in patient group, DD genotype is significantly (p = 0.041) associated with systolic blood pressure (SBP). Moreover, ID genotype is found associated with the presence of cardiovascular diseases. This study concludes that DD genotype is strongly associated with higher SBP in hypertensive patients.

The Top 12 Advances in Vascular Medicine

In the past decade, impressive strides have been made in the diagnosis and management of atherosclerotic, aneurysmal, and thromboembolic diseases, thanks in large part to the explosive growth in both vascular biology and clinical vascular medicine. We review what we consider to be the top 12 advances in this field: the discovery of nitric oxide, the metabolic syndrome, new thrombophilic disorders, therapeutic angiogenesis, endoluminal treatment of chronic venous disease, and a variety of drugs, including sildenafil, cilostazol, low-molecular-weight heparins, oral direct thrombin inhibitors, clopidogrel, statins, and angiotensin-converting enzyme inhibitors and angiotensin-receptor blocking agents.

Relationship of the rs1799752 polymorphism of the angiotensin-converting enzyme gene and the rs699 polymorphism of the angiotensinogen gene to the process of in-stent restenosis in a population of Polish patients with stable coronary artery disease

PURPOSE

The renin-angiotensin-aldosterone system may influence in-stent restenosis (ISR) via angiotensin II, which stimulates the production of growth factors for smooth muscle cells. The aim of this work is to assess the influence of the rs1799752 polymorphism of the angiotensin-converting enzyme (ACE) gene and the rs699 polymorphism of the angiotensinogen (AGT) gene on the ISR in Polish patients with stable coronary artery disease (SCAD) who underwent stent implantation.

MATERIAL/METHODS

Two hundred and sixty-five patients with SCAD were included in the study. All patients underwent stent implantation upon admission to the hospital and had subsequent coronary angiography performed. The patients were divided into two groups - those with significant ISR (n=53) and those without ISR (n=212). The ACE polymorphism was assessed using the classical PCR method and the AGT polymorphism was determined using the TaqMan method for SNP genotyping.

RESULTS

No difference in the frequency of angiographically significant ISR occurrence associated with the different ACE and AGT gene polymorphisms was observed. In a multivariable analysis, after correction for clinical variables, the relationship between the ACE and AGT genotypes within the scope of the analyzed polymorphisms and the process of restenosis was not found using a dominant, recessive and log-additive model. Late lumen loss was also independent of the genotypes of the polymorphisms before and after correction with angiographic variables.

CONCLUSIONS

The rs1799752 polymorphism and the rs699 polymorphism had no relationship with the occurrence of angiographically significant ISR and late lumen loss in a group of Polish patients who underwent metal stent implantation.

Altered aortic shape in bicuspid aortic valve relatives influences blood flow patterns

AIMS

Bicuspid aortic valve (BAV) is known to exhibit familial inheritance and is associated with aortopathy and altered aortic haemodynamics. However, it remains unclear whether BAV-related aortopathy can be inherited independently of valve morphology.

METHODS AND RESULTS

Four-dimensional flow magnetic resonance imaging for the in vivo assessment of thoracic aortic 3D blood flow was performed in 24 BAV relatives with trileaflet aortic valves (age = 40 ± 14 years) and 15 healthy controls (age = 37 ± 10 years). Data analysis included aortic dimensions, shape (round/gothic/cubic), and 3D blood flow characteristics (semi-quantitative vortex/helix grading and peak velocities). Cubic and gothic aortic shapes were markedly more prevalent in BAV relatives compared with controls (38 vs. 7%). Ascending aorta (AAo) vortex flow in BAV relatives was significantly increased compared with controls (grading = 1.5 ± 1.0 vs. 0.6 ± 0.9, P = 0.015). Aortic haemodynamics were influenced by aortic shape: peak velocities were reduced for gothic aortas vs. round aortas (P = 0.003); vortex flow was increased for cubic aortas in the AAo (P < 0.001) and aortic arch (P = 0.004); vortex and helix flows were elevated for gothic aortas in the AAo and descending aorta (P = 0.003, P = 0.029). Logistic regression demonstrated significant associations of shape with severity of vortex flow in AAo (P < 0.001) and aortic arch (P = 0.016) in BAV relatives.

CONCLUSION

BAV relatives expressed altered aortic shape and increased vortex flow despite the absence of valvular disease or aortic dilatation. These data suggest a heritable component of BAV-related aortopathy affecting aortic shape and aberrant blood flow, independent of valve morphology.

A Physiologic Approach to the Pharmacogenomics of Hypertension

Hypertension is a multifactorial condition with diverse physiological systems contributing to its pathogenesis. Individuals exhibit significant variation in their response to antihypertensive agents. Traditional markers, such as age, gender, diet, plasma renin level, and ethnicity, aid in drug selection. However, this review explores the contribution of genetics to facilitate antihypertensive agent selection and predict treatment efficacy. The findings, reproducibility, and limitations of published studies are examined, with emphasis placed on candidate genetic variants affecting drug metabolism, the renin-angiotensin system, adrenergic signalling, and renal sodium reabsorption. Single-nucleotide polymorphisms identified and replicated in unbiased genome-wide association studies of hypertension treatment are reviewed to illustrate the evolving understanding of the disease's complex and polygenic pathophysiology. Implementation efforts at academic centers seek to overcome barriers to the broad adoption of pharmacogenomics in the treatment of hypertension. The level of evidence required to support the implementation of pharmacogenomics in clinical practice is considered.

Are normal-sized ascending aortas at risk of late aortic events after aortic valve replacement for bicuspid aortic valve disease?

OBJECTIVES

Bicuspid aortic valve (BAV)-associated aortopathy has been proposed to progress after isolated aortic valve replacement (AVR) surgery, which has been traditionally used as an argument against a TAVR procedure in this clinical subset. Still, more than half of BAV patients have a normal-sized proximal aorta at the time of AVR surgery. We aimed to analyse the long-term risk of adverse aortic events after isolated conventional AVR surgery for BAV and normal-sized proximal aorta.

METHODS

A total of 200 consecutive patients (mean age 56 ± 13 years, 73% men) with BAV disease and ascending aortic diameter of <40 mm underwent isolated conventional AVR from 1995 through 2008 and were identified from our institutional BAV database. Long-term follow-up data (a total of 1532 patient-years) were obtained for all hospital survivors. Composite adverse aortic/cardiovascular events were defined as the need for redo aortic surgery, the occurrence of aortic dissection/rupture, or sudden cardiac death during follow-up.

RESULTS

A total of 25 (13%) patients died after a mean follow-up of 8.5 ± 5 years post-AVR surgery, which resulted in an overall survival rate of 75 ± 6 and 87 ± 7% at 15 years postoperatively, for BAV-aortic stenosis and BAV-aortic regurgitation, respectively (P = 0.6). An adverse aortic event occurred in 1 (0.5%) study patient, while 5 (2.5%) further patients suffered sudden cardiac death. Only 1 patient required redo aortic surgery. No documented aortic dissection/rupture occurred. Redo AVR surgery due to endocarditis or structural valve degeneration was performed in 6 (3%) patients. The rate of freedom from composite adverse events was 92 ± 5 and 95 ± 4% at 15 years, for the AS and AR subgroups, respectively (P = 0.7).

CONCLUSIONS

BAV patients with aortic valve dysfunction and normal-sized ascending aorta are at considerably low risk of late adverse aortic events after isolated AVR.

Structure and function of the tricuspid and bicuspid regurgitant aortic valve: an echocardiographic study

OBJECTIVES

The emerging new treatment options for aortic valve disease call for more sophisticated diagnostics. We aimed to describe the echocardiographic pathophysiology and characteristics of the purely regurgitant aortic valve in detail.

METHODS

Twenty-nine men, with chronic aortic regurgitation without concomitant heart disease referred for aortic valve intervention, underwent 2D transoesophageal echocardiographic (TEE) examination prior to surgery according to a previously published matrix. Measurements of the aortic valve apparatus in long and short axis view were made in systole and diastole and analysed off-line. The aortic valves were grouped as tricuspid (TAV) or bicuspid (BAV), and classified by regurgitation mechanism.

RESULTS

Twenty-four examinations were eligible for analysis of which 13 presented TAV and 11 BAV. The regurgitation mechanism was classified as dilatation of the aorta in 6 cases, as prolapse in 11 cases and as poor cusp tissue quality or quantity in 7 cases. The ventriculo-aortic junction (VAJ) and valve opening were closely related (TAV r = 0.5, BAV r = 0.73) but no correlation was found between the VAJ and the maximal sinus diameter (maxSiD) or the sinotubular junction (STJ). However, the STJ and maxSiD were significantly related (TAV vs BAV: systole r = 0.9, r = 0.8; diastole r = 0.9, r = 0.7), forming an entity. The conjoined BAV cusps were shorter than the anterior cusps when closed (P = 0.002); the inter-commissural distances of the cusps in the BAV group were significantly different (P = 0.001 resp. 0.03) in both systole and diastole.

CONCLUSIONS

The VAJ was independent of other aortic dimensions and should thereby be considered as a separate entity with influence on valve opening. The detailed 2D TEE measurements of this study add further important information to our knowledge about the function and echocardiographic anatomy of the pathological aortic valve and root either as a stand-alone examination or as a benchmark and complement to 3D echocardiography. This may have an impact on decisions regarding repairability of the native aortic valve.

New insights in the association between bicuspid aortic valve phenotype, aortic configuration and valve haemodynamics

OBJECTIVES

Patients with a bicuspid aortic valve (BAV) present with various phenotypes of the valve, the aortic root (AoR) and/or the ascending aorta (AAo) and various valve haemodynamics (vHs). The aim of the present study was to investigate the association between the above parameters.

METHODS

Between February 1999 and April 2014, the preoperative aortographies of 828 surgical patients with BAV were evaluated. The exact BAV type was classified intraoperatively according to the number and spatial orientation of the raphes.

RESULTS

On analysis of BAV phenotypes and aortic configurations, a weak pattern was revealed (P = 0.01) only for BAV type 0 and AoR dilatation. Including haemodynamics, certain significant patterns emerged: in insufficient BAVs, AoR dilatation was significantly more frequent in type 0, type 1 LR and type 1 RN, whereas AoR + AAo dilatation was more frequent in BAV type 1 LR. In stenotic BAVs, AAo dilatation alone was observed significantly more frequently in BAV type 1 LR and type 0. Combined vHs were associated with AAo and AoR + AAo dilatation in BAV type 2/unicuspid only.

CONCLUSIONS

Associations between the two parameters, BAV type and aortic configuration, were only weak. With the inclusion of haemodynamics significant associations emerged but were not exclusive. In stenotic BAVs, aortic dilatation was more localized to AAo only, supporting the valve-related flow turbulence theory. Insufficient (even trace insufficient) BAVs and also combined lesions in BAV type 2/unicuspid were associated with a more extensive aortopathy (AoR + AAo) in younger patients, indicating a more aggressive gene-related aortopathy.

The influence of bicuspid aortic valves on the dynamic pressure distribution in the ascending aorta: a porcine ex vivo model

OBJECTIVES

The aim of the study was to simulate the effect of different bicuspid aortic valve configurations on the dynamic pressure distribution in the ascending aorta.

METHODS

Aortic specimens were harvested from adult domestic pigs. In Group 1, bicuspidalization was created by a running suture between the left and the right coronary leaflets (n = 6) and in Group 2 by a running suture between the left and the non-coronary leaflets (n = 6). Eleven tricuspid specimens served as controls. Two intraluminal pressure catheters were positioned at the concavity and the convexity of the ascending aorta. The specimens were connected to a mock circulation (heart rate: 60 bpm, target pressure: 95 mmHg). A comparison of the different conditions was also done in a numerical simulation.

RESULTS

At a distal mean aortic pressure of 94 ± 10 mmHg, a mean flow rate of 5.2 ± 0.3 l/min was achieved. The difference of maximal dynamic pressure values (which occurred in systole) between locations at the convexity and the concavity was 7.8 ± 2.9 mmHg for the bicuspid and 1.0 ± 0.9 mmHg for the tricuspid specimens (P < 0.001). The numerical simulation revealed an even higher pressure difference between convexity and concavity for bicuspid formation.

CONCLUSIONS

In this hydrodynamic mock circulation model, we were able to demonstrate that bicuspid aortic valves are associated with significant pressure differences in different locations within the ascending aorta compared with tricuspid aortic valves. These altered pressure distributions and flow patterns may further add to the understanding of aneurismal development in patients with bicuspid aortic valves and might serve to anticipate adverse aortic events due to a better knowledge of the underlying mechanisms.

Wall shear stress and flow patterns in the ascending aorta in patients with bicuspid aortic valves differ significantly from tricuspid aortic valves: a prospective study

AIMS

We compared flow and wall shear stress (WSS) patterns in the ascending aorta of individuals with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) using four-dimensional cardiovascular magnetic resonance (4D-CMR). BAV are known to be associated with dilation and dissection of the ascending aorta. However, the cause of vessel disease in patients with BAVs is unknown. Inborn connective tissue disease and also dilation secondary to increased WSS because of altered blood flow patterns in the ascending aorta are discussed as causes for dilation of the aorta. WSS can be estimated non-invasively by 4D-CMR.

METHODS AND RESULTS

Eighteen, otherwise, healthy individuals with functionally normal BAVs were compared prospectively with an age- and sex-matched control group of healthy individuals with TAV. Blood flow data were obtained by 4D-CMR visualization and WSS was calculated with specific software tools. Eighty-five per cent of the individuals with BAVs showed a high-grade helical flow pattern in the ascending aorta compared with 6% of the individuals with TAV. WSS in the ascending aorta was significantly altered in individuals with BAVs compared with TAV.

CONCLUSION

WSS and flow patterns in the ascending aorta in patients with BAVs without concomitant valve or vessel disease are significantly different compared with TAV. The significantly higher shear forces may have an impact on the development of aortic dilation in patients with BAVs.

Tissue-Specific Upregulation of Angiotensin-Converting Enzyme 1 in Spontaneously Hypertensive Rats Through Histone Code Modifications

The renin-angiotensin system has been implicated in the development of hypertension and damages several organs. The expressions of the components of a local renin-angiotensin system (RAS) in the hypertensive rats differ from those of the normotensive rats. We hypothesized that local tissue-specific upregulation of angiotensin-converting enzyme 1 (ACE1) in hypertension is caused by epigenetic changes. Adrenal gland, aorta, heart, kidney, liver, and lung tissues were excised from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). Ace1 mRNA and protein expressions were measured by real-time PCR and Western blot, respectively. Promoter methylation was revealed by bisulfite sequencing. Histone modifications, such as histone 3 acetylation (H3Ac), fourth lysine trimethylation (H3K4me3), and ninth lysine dimethylation (H3K9me2), were quantified by chromatin immunoprecipitation (ChIP), followed by real-time PCR. The expressions and associations of chromatin remodeling genes were analyzed by real-time PCR and ChIP, respectively. Local tissues from SHRs showed higher expressions of Ace1 mRNA and protein than those from the WKY rats. Ace1 promoter was mostly unmethylated in all of the tissues from both strains. The Ace1 promoter regions of SHR tissues were more enriched with H3Ac and H3K4me3, except in the lungs. The adrenal glands, hearts, and kidneys of SHRs showed less enrichment with H3K9me2. Valsartan treatment in SHRs decreased local Ace1 mRNA and protein expressions, which were accompanied by higher H3K9me2, as well as less H3Ac and H3K4me3. In conclusion, ACE1 is upregulated in local tissues of SHRs via histone code modifications.

Safety and efficacy of the sulfydryl ACE-inhibitor zofenopril in the management of cardiovascular disease

In the 1970s, pharmacological therapy interrupting the renin-angiotensin system was considered beneficial for patients with high-renin hypertension. Angiotensin-converting enzyme (ACE) inhibitors proved to be effective not only in patients with high renin and elevated blood pressure, but also in many hypertensive patients with normal levels of plasma renin activity. ACE inhibitors are used in a wide range of chronic illnesses such as atherosclerosis, hypertension, myocardial infarction, heart failure, diabetic complications, and stroke. To date, more than ninety controlled clinical trials evaluating the beneficial effects of 14 different ACE inhibitors were conducted. Moreover, data from experimental studies showed that ACE inhibitors can attenuate the development of atherosclerosis, oxidative stress, and vascular inflammation in a wide range of species indicating that ACE inhibition also favourably affects the vasculature. More than fifteen years ago, the bi-sulfydryl ACE-inhibitor zofenopril has shown an excellent clinical safety and efficacy in patients with hypertension and in those with myocardial infarction. More recently, this compound exhibited a potent antioxidant and antiatherosclerotic effect indicating a clinical useful vasoprotective action.

Augmentation index and the evolution of aortic disease in marfan-like syndromes

BACKGROUND

The augmentation index at a heart rate of 75 beats/min (AIx@HR75) and central pulse pressure (CPP) can be measured noninvasively with applanation tonometry (APT). In this observational study, we investigated the relationship between AIx@HR75, CPP and aortic disease in patients with Marfan-like syndromes.

METHODS

We performed APT in 78 consecutive patients in whom classic Marfan syndrome (MFS) had been excluded (46 men and 32 women aged 34 +/- 13 years). These patients comprised 9 persons with MFS-like habitus, 6 with a bicuspid aortic valve (BAV), 5 with MASS phenotype, 3 with vascular type of Ehlers-Danlos syndrome (EDS), 3 with familial thoracic aortic aneurysm, 2 with Loeys-Dietz syndrome (LDS), 1 with mitral valve prolapse syndrome, 1 with familial ectopia lentis, and 48 persons with Marfan-like features but no defined syndrome. During 20 +/- 18 months after APT, we observed progression of aortic diameters in 15 patients, and aortic surgery or aortic dissection in 3 individuals.

RESULTS

All 11 patients with Marfan-like syndromes and progression of aortic disease exhibited AIx@HR75 > or =11%, including 8 individuals with aortic diameters < or =95th percentile of normal at baseline. Similarly, all 7 individuals without any defined syndrome but progression of aortic diameters exhibited AIx@HR75 >11%, including 6 individuals with aortic diameters < or =95th percentile at the time of APT. Aortic disease did not evolve at AIx@HR75 <11%. CPP is also related to aortic disease progression.

CONCLUSIONS

Aortic disease evolution relates to AIx@HR75 and CPP in Marfan like syndromes. Larger studies with comprehensive clinical and echocardiographic follow-up over long time intervals will be required to establish APT for prediction of aortic disease evolution in Marfan-like syndromes.

ACE (I/D) polymorphism and response to treatment in coronary artery disease: a comprehensive database and meta-analysis involving study quality evaluation

BACKGROUND

The role of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in modifying the response to treatment modalities in coronary artery disease is controversial.

METHODS

PubMed was searched and a database of 58 studies with detailed information regarding ACE I/D polymorphism and response to treatment in coronary artery disease was created. Eligible studies were synthesized using meta-analysis methods, including cumulative meta-analysis. Heterogeneity and study quality issues were explored.

RESULTS

Forty studies involved invasive treatments (coronary angioplasty or coronary artery by-pass grafting) and 18 used conservative treatment options (including anti-hypertensive drugs, lipid lowering therapy and cardiac rehabilitation procedures). Clinical outcomes were investigated by 11 studies, while 47 studies focused on surrogate endpoints. The most studied outcome was the restenosis following coronary angioplasty (34 studies). Heterogeneity among studies (p < 0.01) was revealed and the risk of restenosis following balloon angioplasty was significant under an additive model: the random effects odds ratio was 1.42 (95% confidence interval:1.07-1.91). Cumulative meta-analysis showed a trend of association as information accumulates. The results were affected by population origin and study quality criteria. The meta-analyses for the risk of restenosis following stent angioplasty or after angioplasty and treatment with angiotensin-converting enzyme inhibitors produced non-significant results. The allele contrast random effects odds ratios with the 95% confidence intervals were 1.04(0.92-1.16) and 1.10(0.81-1.48), respectively. Regarding the effect of ACE I/D polymorphism on the response to treatment for the rest outcomes (coronary events, endothelial dysfunction, left ventricular remodeling, progression/regression of atherosclerosis), individual studies showed significance; however, results were discrepant and inconsistent.

CONCLUSION

In view of available evidence, genetic testing of ACE I/D polymorphism prior to clinical decision making is not currently justified. The relation between ACE genetic variation and response to treatment in CAD remains an unresolved issue. The results of long-term and properly designed prospective studies hold the promise for pharmacogenetically tailored therapy in CAD.

Behaviour of polyester grafts in adult patients with repaired coarctation of the aorta

AIMS

Whatever the technique used for surgical or endovascular repair of a coarctation of the aorta (CA), long-term complications might occur. Aneurysm formation after patch angioplasty is not uncommon and may lead to a life-threatening condition. Therefore, we were interested in the long-term results of different types of tube grafts, from which a lower degree of dilatation is expected.

METHODS AND RESULTS

All patients, currently older than 16 years, who underwent (redo) surgery for CA, and in whom a tube graft was inserted, were selected from the database of congenital heart disease of our hospital. Follow-up data were collected by reviewing the patients' files. The degree of graft dilatation was calculated for each patient. Fifty-three patients (41 males, median age 33.1 years, Q1-Q3 29.9-40.2 years) could be included in the study, in which 20 (38%) 'Gelseal', 12 (23%) 'Gelsoft', 8 (15%) 'Gelweave', and 13 (24%) older types of grafts were used. Twenty patients underwent a primary repair and in all others a tube graft was implanted after a previous patch angioplasty. The median graft diameter (manufacturer size) at implantation was 20 mm (Q1-Q3 16-22 mm). The median follow-up time of the grafts was 13.1 years (Q1-Q3 9.0-17.2 years). The graft size increased to a median value of 26 mm (Q1-Q3 22-30 mm) (median 50% increase in diameter, range 0-271%, P < 0.0001). The diameter of six grafts remained unchanged during follow-up. Three deaths occurred, of whom two were cardiac-related. False aneurysms occurred in four patients, graft aneurysm in two, endarteritis in two, and graft stenosis in one.

CONCLUSION

Nearly, all tube grafts dilated up to 50% of the manufacturer diameter during follow-up. Re-interventions were inevitable in more than 10 per cent of the cases, primarily because of (false) aneurysm formation. Our series illustrates that late complications are not uncommon, so that rigorous follow-up of these CA patients remains mandatory.

Pharmacogenomics of Renin Angiotensin System Inhibitors in Coronary Artery Disease

Renin Angiotensin System (RAS) inhibitors comprise some of the most commonly used medications in coronary artery disease (CAD) and its related syndromes. Unfortunately, significant inter-patient variability seems likely in response to these agents; of which, the influence of genetic determinants is of interest. This review summarizes the available RAS inhibitor pharmacogenomic studies which have evaluated RAS polymorphisms that either elucidate mechanism via surrogate endpoint measurements, or predict efficacy via clinical outcomes in CAD related syndromes.Regardless of the endpoint, none of the RAS genotypes conclusively predicts efficacy of RAS inhibitors. In fact, the results of the pharmacogenomic studies were often in direct conflict with one another. Varied results appear due to methodological limitations (e.g., inadequate study power, genotyping error, methods of endpoint measurement), study conceptualization (e.g., overestimating the contribution of polymorphism to disease, lack of haplotype approach), and differences between studies (e.g., genotype frequency, study subject characteristics, the specific medication and dose used). Thus investigators should consider the various methodological limitations to improve upon the current approach to RAS inhibitor pharmacogenomic research in the vast CAD population.

Endothelial function and cerebrovascular disease: Implications for diagnosis and treatment

Cerebrovascular disease remains one of the most common causes of morbidity and mortality in the United States. There is strong evidence to implicate endothelial dysfunction in the initiation and progression of atherosclerosis and its complications. It is now well known that endothelial dysfunction represents a systemic syndrome involving multiple vascular beds, including the cerebral vasculature. Currently, no gold standard treatment for endothelial dysfunction exists. Nonetheless, several treatment strategies have been found to be helpful in improving endothelial function. A few of these strategies have been implicated in stroke risk reduction as well, adding another line of evidence to the relationship between endothelial function and cerebrovascular disease.

Pharmacogenomics in cardiovascular disease: the role of single nucleotide polymorphisms in improving drug therapy

Pharmacogenomics is the study of how an individual's genetic inheritance affects the body's response to drugs. Pharmacogenomics holds the promise that drugs might one day be tailor-made for individuals and adapted to an individual's genetic makeup. Several studies have shown that both adverse and beneficial responses to cardiovascular drugs can be influenced by single nucleotide polymorphisms in genes coding for metabolising enzymes, drug transporters and drug targets. Despite the large amount of data about gene-drug interactions, the translation of pharmacogenomics in clinical practise is slow. To improve this, there is a need of new technology and large prospective trials allowing for simultaneous analysis of multiple genetic variants in molecular pathways that could affect drug disposition and action.

Comparison of the effect of enalapril and losartan in conjunction with surgical coronary revascularisation versus revascularisation alone on systemic endothelial function

OBJECTIVES

To investigate the effect of enalapril, losartan, and surgical coronary revascularisation on endothelial function, and the role of the angiotensin converting enzyme (ACE) insertion (I)/deletion (D) polymorphism.

DESIGN

Randomised, controlled, blinded end point study.

SETTING

University tertiary referral cardiac centre.

PATIENTS AND INTERVENTIONS

49 men awaiting coronary artery bypass grafting (CABG) were randomly assigned to treatment with losartan, enalapril, or control for two months before and three months after surgery.

MAIN OUTCOME MEASURES

Endothelial function was blindly analysed by brachial artery flow mediated dilatation (FMD) and ACE I/D genotype was determined.

RESULTS

FMD was impaired at baseline (1.0-1.7%) and after five months had improved to 5.2% with enalapril (p = 0.015), 5.0% with losartan (p = 0.0004), and 3.0% with CABG alone (p = 0.05). Patients with the II genotype had lower baseline FMD than those with DI or DD (0.1% v 1.7%, p = 0.038) and after enalapril or losartan treatment had greater improvement in FMD (mean (SEM) 7.1 (1.1)%) than patients with DI (3.1 (1.3)%, p = 0.024) or DD genotype (3.1 (1.1)%, p = 0.02).

CONCLUSIONS

Enalapril and losartan, with surgical coronary revascularisation, significantly improve systemic endothelial function. Revascularisation alone produces a quantitatively smaller, but still significant, improvement. The ACE genotype significantly modulates this response. Patients with the II genotype have a more pronounced impairment in endothelial function at baseline and a greater improvement in response to treatment with these agents.

Clinical impact of vasomotor function assessment and the role of ACE-inhibitors and statins

Impaired endothelial function is recognised as one of the earliest events of atherogenesis. Endothelium-dependent vasomotion has been the principal method to assess endothelial function. In this article, we will discuss the clinical value of the different techniques to evaluate endothelium-dependent vasomotion. To date, there seems not to be a simple and reliably endothelial function test to identify asymptomatic subjects at increased risk for cardiovascular disease in clinical practice. Recent studies indicate that pharmacological interventions, in particular with ACE-inhibitors and statins, might improve endothelial function. However, there is no solid evidence that improvement of endothelial function is a necessity for the observed reduction in cardiovascular events by these compounds. Overall, at this moment, there is no place in clinical practice for the use of endothelial function as a method for risk assessment or target of pharmacological interventions.

Improved Endothelium Dependent Vasodilation in Endurance Athletes and Its Relation With ACE I/D Polymorphism

BACKGROUND

Aerobic exercise enhances endothelium-dependent vasodilation in healthy individuals. It is thought that exercise increases nitric oxide (NO) production and decreases NO inactivation, leading to an increase in NO bioavailability. Angiotensin II and NO have important roles in maintaining vascular tone. There are polymorphisms of the angiotensin converting enzyme (ACE) gene and the presence of the deletion (D) allele has been associated with higher concentrations of circulating and tissue ACE. In this study, the relationship between endothelial function and ACE gene polymorphisms was investigated in athletes and sedentary subjects.

METHODS AND RESULTS

The study group comprised 56 endurance athletes and 46 sedentary subjects who underwent brachial artery ultrasonographic examination. ACE insertion (I) and D allele frequencies were analyzed in all patients. Baseline brachial artery diameter and resting blood flow were similar in athletes and controls (p > 0.05). The flow-mediated dilation (FMD) was 8.48+/-3.65% in athletes and 5.16+/-2.5% in controls (p = 0.0001). FMD was significantly different between ACE genotypes in the athletes (p < 0.0001): it was higher in ACE II (10.5+/-1.6%) subjects than in the DI (8.4+/-2.3%) or DD (7+/-1.2%) subgroups.

CONCLUSION

Regular isotonic exercise can improve endothelium-dependent vasodilation especially in those with the ACE II genotype.

ACE inhibitors and angiotensin II receptor antagonists

The biological actions of angiotensin II (ANG), the most prominent hormone of the renin-angiotensin-aldosterone system (RAAS), may promote the development of atherosclerosis in many ways. ANG aggravates hypertension, metabolic syndrome, and endothelial dysfunction, and thereby constitutes a major risk factor for cardiovascular disease. The formation of atherosclerotic lesions involves local uptake, synthesis and oxidation of lipids, inflammation, as well as cellular migration and proliferation--mechanisms that may all be enhanced by ANG via its AT1 receptor. ANG may also increase the risk of acute thrombosis by destabilizing atherosclerotic plaques and enhancing the activity of thrombocytes and coagulation. After myocardial infarction, ANG promotes myocardial remodeling and fibrosis, and its many pathological mechanisms deteriorate the prognosis of these high-risk patients in particular. Therapeutically, inhibitors of the angiotensin I-converting enzyme (ACEI) and AT1 receptor blockers (ARB) are available to suppress the generation and cellular signaling of ANG, respectively. Despite major differences in the efficacy of ANG suppression and the modulation of other hormones and receptors, both classes of drugs are generally effective in attenuating numerous pathomechanisms of ANG in vitro, and in diminishing the development of atherosclerotic lesions and restenosis after angioplasty in various animal models. In clinical therapy, ACEI and ACE are well-tolerated antihypertensive drugs that also improve the prognosis of heart failure patients. After myocardial infarction and in stable coronary heart disease, ACEI have been shown to reduce mortality in a manner independent of hemodynamic alterations. However, there is little evidence that inhibitors of the RAAS may be effective against arterial restenosis, and a possible benefit of these substances compared to other antihypertensive drugs in the primary prevention of coronary heart disease in hypertensive patients is still a matter of debate, possibly depending on the specific substance and condition being investigated. As such, the general clinical efficacy of ACEI and ARB may be due to a positive influence on hemodynamic load, vascular function, myocardial remodeling, and neuro-humoral regulation, rather than to a direct attenuation of the atherosclerotic process. Further therapeutic advances may be achieved by identifying optimum drugs, patient populations, and treatment protocols.

Beneficial effects of quinaprilat on coronary vasomotor function, endothelial oxidative stress, and endothelin activation after human heart transplantation

BACKGROUND

We evaluated the potential of angiotensin-converting enzyme inhibition (ACEI) to modulate resting coronary vasomotor tone and endothelial dysfunction, and to decrease vascular oxidative stress and endothelin (ET)-1 activity in human heart transplant recipients.

METHODS

Coronary vasomotor responses and transcardiac metabolism of glutathione, oxidized glutathione, and ET-1 were determined before and after quinaprilat infusion in 32 heart transplant recipients. Furthermore, the potential effects of ACEI on endothelial oxidative stress, ET-1 activity, and nitrosoglutathione formation were investigated using endothelial cell cultures.

RESULTS

Epicardial diameter increased in response to quinaprilat by 6% +/- 1% (proximal segments; P<0.05) and 14% +/- 3% (distal segments; P<0.01). Coronary flow velocity increased by 2.2 +/- 0.2 (P<0.03). Coronary vasodilation to quinaprilat was negatively correlated with preexisting functional and structural coronary alterations. Quinaprilat selectively improved epicardial vasomotor response in segments with endothelial dysfunction, whereas microvascular endothelial dysfunction was unchanged. Transcardiac glutathione and big ET levels decreased after quinaprilat, whereas oxidized glutathione and ET-1 concentrations remained unchanged. Cell culture studies showed antioxidative effects of quinaprilat, revealed concentration-dependent down-regulation of endothelial ET-1 release, and indicated formation of nitrosoglutathione by quinaprilat. CONCLUSION.: ACE regulates resting coronary vasomotor tone. Quinaprilat reduces vascular oxidative stress and ET-1 activity and mediates formation of nitrosoglutathione, effects that might contribute to long-term vasculoprotective effects of ACEI after heart transplantation.

Pharmacogenomics and renal drug disposition in the newborn

Genetic polymorphisms in the genes coding for drug metabolizing enzymes, drug transporters, and drug receptors are major determinants of an individual's response to drugs. The potential interactions of pharmacogenomics of renal drug transporters and drug receptors with renal drug disposition and the immature kidneys are briefly reviewed. Examples of gene polymorphisms seen in the RAAS (renin angiotensin system), beta-adrenergic receptors, dopamine receptors and cytochrome P450 and their potential clinical impact are discussed. The human newborn has deficient hepatic and renal drug metabolism and disposition. This immaturity in drug-handling capacity may potentially be superimposed to genetic polymorphisms determining drug metabolism and transport thereby substantially increasing interpatient variability in drug dose requirements and in drug responses in the newborn. Pharmacogenomics is a tool that can be used to individualize drug therapy in newborns to minimize adverse drug effects and to optimize efficacy.

Angiotensin-Converting Enzyme Insertion/Deletion Polymorphism Modulates Coronary Release of Tissue Plasminogen Activator in Response to Bradykinin

The aim of this study was to assess the relationship between the angiotensin converting enzyme gene (ACE) genotype and endothelium-dependent coronary vasomotor and fibrinolytic activity. The ACE DD genotype has been reported to be a risk factor for myocardial infarction. However, the mechanism is unknown. The fibrinolytic and renin-angiotensin systems are linked via ACE at the vascular beds. We studied 73 patients (II: n=24; ID: n=37; DD: n=12) who underwent diagnostic cardiac catheterization. Graded doses of bradykinin (BK) (0.2, 0.6, 2.0 microg/min) and acetylcholine (30,100 microg/min) were administered into the left coronary artery. Coronary blood flow (CBF) was evaluated by measuring Doppler flow velocity. Blood samples were taken from the aorta (Ao) and the coronary sinus (CS). Coronary release of tPA antigen was determined as a CS-Ao gradientXCBFX[(100-hematocrit) / 100]. ACE genotypes were determined using polymerase chain reaction. The ACE genotype did not appear to affect coronary macro- and microvascular responses induced by BK or acetylcholine. Coronary tissue plasminogen activator (tPA) release induced by BK was depressed in subjects with the ACE DD genotype. ACE levels in the DD genotype were significantly higher than those in the ID or II genotype. In all of the subjects, there was a significant negative correlation between the serum level of ACE activity and net coronary tPA release in response to BK at 0.6 microg/min. In conclusions, the DD genotype of the ACE gene impairs the coronary release of tPA induced by BK.

Failure to prevent progressive dilation of ascending aorta by aortic valve replacement in patients with bicuspid aortic valve: comparison with tricuspid aortic valve

BACKGROUND

Patients with bicuspid aortic valve (BAV) have been frequently complicated with ascending aortic dilation possibly because of hemodynamic burdens by aortic stenosis (AS) or regurgitation (AR) or congenital fragility of the aortic wall.

METHODS AND RESULTS

To clarify if the aortic dilation could be prevented by aortic valve replacement (AVR) in BAV patients, we studied 13 BAV (8 AR dominant, 5 AS dominant) and 14 tricuspid aortic valve (TAV) patients (7 AR, 7 AS) by echocardiography before and after AVR (9.7+/-4.8 years). We also studied 18 BAV (11 AR, 7 AS) without AVR. Diameters of the sinuses of Valsalva, sinotubular junction and the proximal aorta were measured. The annual dilation rate was calculated by dividing changes of diameters during the follow-up period by the body surface area and the observation interval. We found that aortic dilation in BAV patients tended to be faster than that in TAV patients, although a significant difference was found only at the proximal aorta (0.18+/-0.08 versus -0.08+/-0.08 mm/(m2/year), P=0.03). BAV patients with and without AVR showed similar progressive dilation. AR dominant group showed tendency of more progressive dilation than AS dominant group in BAV, although it did not reach statistical significance. TAV patients did not show further aortic dilation after AVR.

CONCLUSIONS

AVR could not prevent progressive aortic dilation in BAV. Since the aorta did not dilate in TAV, progressive aortic dilation in BAV seems mainly due to the fragility of the aortic wall rather than hemodynamic factors.

Stability of ascending aortic dilatation following aortic valve replacement

BACKGROUND

Replacement of the ascending aorta (Asc Ao) at the time of aortic valve replacement (AVR) is controversial because the risk of progressive dilatation following valve replacement is uncertain. Our aim was to determine the natural history of ascending aortic dilatation following AVR.

METHODS AND RESULTS

We studied 185 patients undergoing AVR at our institution between 1992 and 1999. Clinical and echocardiographic data were obtained by merging our institutional echocardiographic database with the DHMC component of the Northern New England Cardiovascular Disease Study Group database. Baseline Asc Ao measurements obtained from intraoperative transesophageal echocardiograms or early (<8 weeks) postoperative transthoracic echocardiograms were compared with late follow-up measurements (mean follow-up 30.0+/-23.4 months). During follow-up, there was no increase in the mean Asc Ao diameter (3.6+/-0.6 cm versus 3.6+/-0.6 cm, p=NS). Progressive aortic dilatation, defined as an increase in diameter >0.3 cm, occurred in 27/185 patients (15%). Baseline Asc Ao dilatation (>or=3.5 cm) was present in 107/185 patients (58%). In this subset of patients, there was no increase in mean Asc Ao diameter (4.0+/-0.4 versus 3.9+/-0.6 cm, p=NS) and progressive aortic dilatation occurred in only 10 patients (9.3%). No patients with baseline aortic dilatation (range, 3.5 to 5.3 cm) dilated beyond 5.5 cm on follow-up (range, 2.4 to 5.5 cm). There were no clinical or valvular characteristics that predicted progressive Asc Ao dilatation.

CONCLUSIONS

An increase in Asc Ao dilatation occurs infrequently following AVR and therefore, argues against routine Asc Ao replacement at the time of AVR.

Abnormal coronary microvascular endothelial function in humans with asymptomatic left ventricular dysfunction

BACKGROUND

Coronary endothelial dysfunction may potentially lead to myocardial ischemia and to the progression of heart failure. Though endothelial dysfunction is associated with advanced heart failure in humans, relatively little is known regarding their temporal relationship. Thus, the current study was designed to test the hypothesis that coronary endothelial dysfunction is present in patients with asymptomatic left ventricular dysfunction.

METHODS AND RESULTS

Three hundred patients without symptoms of heart failure, with normal or mildly diseased coronary arteries at angiography underwent coronary vascular reactivity evaluation using intracoronary adenosine, acetylcholine (ACH) and nitroglycerin. Patients were divided into 2 groups based on the left ventricular ejection fraction (EF): patients with asymptomatic left ventricular dysfunction (ALVD), EF <45% (n = 11); and patients with EF > or =45% (n = 289, controls). Except for a lower high-density lipoprotein level in patients with ALVD, there were no significant differences between the groups in regards to conventional cardiovascular risk factors. There was no difference in the change (mean +/- SE) in epicardial diameter in response to ACH (-21.7% +/- 7.2% vs -13.8% +/- 1.5%, P =.3). The change in coronary blood flow in response to ACH was significantly attenuated in the patients with ALVD when compared to the controls (-18.5% +/- 14.9% vs 74.0% +/- 7.2%, P <.013). By multivariate analysis, EF was an independent predictor of coronary microvascular dilation with ACH (P <.001).

CONCLUSION

The current study demonstrates that coronary microvascular endothelial dysfunction is present in ALVD. Thus, coronary endothelial dysfunction may be an early event in the pathophysiology of heart failure.

Correlation of Angiotensin-converting enzyme gene polymorphism with effect of antihypertensive therapy by Angiotensin-converting enzyme inhibitor

BACKGROUND

The correlation of the angiotensin-converting enzyme insertion/deletion polymorphism with essential hypertension shown in previous studies is controversial, and the responses of hypertensive patients with different angiotensin-converting enzyme genotypes to treatment with an angiotensin-converting enzyme inhibitor merits investigation.

METHODS

Eighty-nine patients with essential hypertension and 102 normotensive subjects were included in this study. All subjects were genotyped by polymerase chain reaction for the insertion/deletion polymorphism of the angiotensin-converting enzyme gene. Blood pressure was measured before and after taking Benazepril 10 mg, once daily, for 2 months.

RESULTS

The genotype and allele frequencies were similar (chi(2) = 0.64, P =.73; chi(2) = 0.36, P =.55, respectively). The reduction of both systolic and diastolic blood pressure in the DD genotype was significantly greater than in the II genotype (10.13 +/- 4.91 vs 5.37 +/- 2.79, P <.01; 7.47 +/- 3.50 vs 4.71 +/- 2.40, P <.05, respectively).

CONCLUSIONS

No significant association of angiotensin-converting enzyme gene polymorphism with essential hypertension was found. Angiotensin-converting enzyme gene polymorphism might be related to the antihypertensive response to an angiotensin-converting enzyme inhibitor in hypertensive patients.

Bicuspid aortic valve associated with aortic dilatation: a community-based study

OBJECTIVE

This study was undertaken to examine the association between bicuspid aortic valve (BAV) and aortic dilatation in the community. The association between BAV and aortic dilatation has been reported predominantly in retrospective studies in patients mostly with valvular dysfunction or selected surgical patients from tertiary referral centers. An independent association of BAV and aortic dilatation in a community-based study has not been demonstrated.

METHODS AND RESULTS

In a geographically defined population of Olmsted County, Minnesota, residents with BAV (n=44, age 35+/-13 years) without hemodynamically significant obstruction or regurgitation and matched controls with normal tricuspid aortic valves were identified by transthoracic echocardiography. The two groups were compared with respect to measurements of the aorta. The BAV and control groups differed with respect to size of the aortic anulus (23.2+/-2.4 versus 21.6+/-2.4 mm; P=0.002), aortic sinus (33.5+/-4.6 versus 30.3+/-4.1 mm; P=0.0001), and proximal ascending aorta (33.3+/-6.5 versus 27.9+/-3.6 mm; P=0.0001). There was no difference in the size of the aortic arch (24.2+/-3.6 versus 25.3+/-3.4 mm; P=0.16). These differences were maintained when the groups were stratified by sex and blood pressure. The relationship between bicuspid aortic valve and aortic dilatation was maintained when adjusting for factors related to fluid mechanics and hemodynamics such as systolic blood pressure, diastolic blood pressure, left ventricular ejection time, and peak aortic valve velocity.

CONCLUSIONS

In a community-based study, BAV is associated with an alteration of aortic dimensions even in the absence of hemodynamically significant aortic valve stenosis or regurgitation.

Kidney disease, genotype and the pathogenesis of vasculopathy

PURPOSE OF REVIEW

The two leading causes of end-stage renal disease in the United States are diabetes mellitus and hypertensive nephrosclerosis, accounting for over two-thirds of all cases. In many patients both diseases are associated with small- and large-vessel disease, commonly attributed to hypertension or accelerated atherosclerosis. Recent investigations, however, have suggested that renal large-vessel and microvascular disease may be independent contributors to progressive kidney failure.

RECENT FINDINGS

Although genes have not been definitely linked to renal vascular disease, population- and family-based epidemiology of kidney disease, segregation analysis of Pima and Caucasian families in which diabetic nephropathy is clustered, and the positional cloning of genes responsible for rare, familial glomerulosclerosis syndromes support the hypothesis that genes regulate the pathogenesis of renal disease. This review highlights developments in our current understanding of vasculopathy and its role in renal disease, and it summarizes evidence suggesting that genetic determinants for the vascular phenotype are associated with common causes of chronic renal failure.

SUMMARY

With the application of genomics and proteomics methodologies to drug discovery, the identification of renal susceptibility genes should identify new mechanisms of progressive renal disease pathogenesis and generate novel target molecules for the treatment of kidney disease.

No association between high-altitude tolerance and the ACE I/D gene polymorphism

PURPOSE

The absence (deletion allele [D]) of a 287 base-pair fragment in the ACE gene is associated with higher ACE tissue activity than its presence (insertion allele [I]) and, as such, may enhance vasoconstriction and fluid retention through increased levels of angiotensin II and aldosterone. Because fluid retention is found in acute mountain sickness (AMS) and exaggerated pulmonary hypertension is essential in the pathophysiology of high-altitude pulmonary edema (HAPE), we hypothesized that the DD genotype is associated with increased susceptibility to these illnesses.

METHODS

ACE genotype was thus determined in 83 mountaineers staying over night at 4559 m and related to AMS symptoms. Genotype was similarly determined in 76 mountaineers who had participated in previous studies at 4559 m; 38 of the latter group had a history of HAPE, and 25 had developed HAPE again during these studies.

RESULTS

The allele frequency was in Hardy-Weinberg equilibrium in both investigations. Neither the history nor the observed episodes of HAPE nor the prevalence of AMS defined as an AMS-C score >/= 0.70 (environmental symptom questionnaire) in the first study or in both studies taken together were significantly different between the genotypes DD, ID, and II.

CONCLUSION

We conclude that I/D-ACE gene polymorphism has no important effect on susceptibility to AMS or HAPE.

Drug target pharmacogenomics: an overview

Pharmacogenomics is a field aimed at understanding the genetic contribution to variability in drug efficacy and toxicity. The goal is to be able to select the drugs with the greatest likelihood of benefit and the least likelihood of harm in individual patients, based on their genetic make-up. Pharmacogenetics has historically been a field focused primarily on genetic polymorphisms in drug metabolizing enzymes and their impact on drug efficacy and toxicity. More recently, investigators have begun to study the relationship between drug target polymorphisms and drug efficacy and toxicity. There are now numerous examples in the literature of associations between drug target polymorphisms and drug effect. Drug targets can be broken into three main categories: the direct protein target of the drug, signal transduction cascades or downstream proteins, and disease pathogenesis proteins. While the drug target pharmacogenetics literature provides 'proof of concept' that genetic variability contributes to the variability in drug response, the data are not to the point of being clinically useful in most cases. Specific problems to date include the inability of a single polymorphism to be highly predictive of response, and inconsistencies across studies of the same polymorphism. It seems likely that an important factor in the above limitations is the approach of focusing on a single polymorphism in a single gene. Given that most drug responses involve a large number of proteins, all of whose genes could have several polymorphisms, it seems unlikely that a single polymorphism in a single gene would explain a high degree of drug response variability in a consistent fashion. Thus, it seems that a polygenic, or genomic approach will be more appropriate. Candidate gene and genome scanning approaches to pharmacogenomics have shown promise in relating drug target polymorphisms to response or toxicity, and pharmacogenomic strategies for drug discovery and drug development are now being implemented by most major pharmaceutical companies. Pharmacogenomics has the potential to significantly enhance the ability of clinicians to use medications in a safe and effective manner and, as such, represents an exciting field with tremendous clinical potential.

Progression of atherosclerosis in patients with peripheral arterial disease as a function of angiotensin-converting enzyme gene insertion/deletion polymorphism

Angiotensin-converting enzyme insertion/deletion (I/D) gene polymorphism plays a role in determining the inter-individual variability of circulating angiotensin-converting enzyme activity and intracellular angiotensin-converting enzyme levels. Angiotensin-converting enzyme, as a key enzyme in the renin-angiotensin system, catalyzes the activation of the vasoconstricting and proliferation-stimulating angiotensin II and breaks down the vasodilatory peptide bradykinin. It is assumed that the excess supply of angiotensin II (due to the deletion polymorphism of the angiotensin-converting enzyme gene) contributes to endothelial dysfunction and in this way promotes the onset and progression of atherosclerosis. The aim of this study was to test whether the presence of the deletion allele of the angiotensin-converting enzyme gene predisposes a more rapid systemic progression of a preexisting peripheral arterial disease. To this end, the course of disease was surveyed for an average of 5 years in 97 patients who were angiotensin-converting enzyme gene-typed and suffered from a stable stage II peripheral arterial disease according to Fontaine. These patients did not suffer from an additional coronary artery disease, a cerebrovascular disease, or other serious illness. A local progression in the periphery or a systemic progression in the coronary or cerebrovascular areas was regarded as study endpoints. Of the patients, 49.5% showed an atherosclerosis progression during the surveillance period. With II-carriers, a progression was registered in 42.1% and with DD carriers, progression was seen in 59.4%. D/I allele frequencies were seen in patients with progression at a level of 0.60/0.40 vs 0.55/0.45 for patients without progression. The average duration of disease in stable stage II (before progression appeared) amounted to 108 +/- 14 months for II carriers, 88 +/- 8 months for ID carriers, and 92 +/- 11 months for DD carriers (p = 0.21). Based on these findings, the deletion polymorphism of the angiotensin-converting enzyme gene is not an independent risk factor for progression of atherosclerosis in patients with peripheral arterial disease.

Quinapril prevents restenosis after coronary stenting in patients with angiotensin-converting enzyme D allele

Restenosis after coronary artery stent implantation is attributed chiefly to intimal hyperplasia, which is prevented experimentally by angiotensin-converting enzyme (ACE) inhibitors. Therefore, the present study investigated whether the effect of quinapril, a tissue-specific ACE inhibitor, on the prevention of coronary restenosis differs according to ACE polymorphism. One hundred consecutive patients with successful stent implantation were randomly assigned to quinapril and control groups. Both follow-up angiography and ACE polymorphism analysis were obtained from 92 patients (control, 46; quinapril treatment, 46). The prevalence of risk factors did not differ statistically according to quinapril treatment or ACE genotypes. There was no statistically significant difference in the occurrence of restenosis 6 months after stenting between the groups. Quantitative coronary angiography revealed that quinapril treatment resulted in significantly higher minimal lumen diameter and significantly lower percent diameter stenosis (22.9 +/- 22.6 vs 37.1 +/- 19.7% in the control group, p < 0.05) in patients with the D allele although there was no difference in those with the II genotype. In addition, intravascular ultrasound revealed that quinapril treatment significantly prevented the loss of minimal lumen cross-sectional area and the increase in percent area stenosis (34.5 +/- 14.0 vs 53.3 +/- 16.4% in the control group, p < 0.05) in patients with the D allele compared to those with the II genotype. These results suggest that the administration of ACE inhibitors for the attenuation of lumen loss after coronary stent implantation is best for subjects with the D allele of the ACE genotype.