MASTER MINI KADATE

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TINJAUAN PUSTAKA

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Introduction

Coronary heart disease (CHD) becomes a major global public

health problem since the last two decades. Although there has

been recent decline in age-standardized cardiovascular mortality,

the prevalence of CHD remains high due to increased life expec-

tancy and changing in life-style of the population. CHD is the

leading cause of death in the United States, responsible for

nearly 20% of all deaths

(1)

. Currently, CHD has been also the

leading contributor for death and disability in developing countries.

The World Health Organization estimates that CHD will account

for 6% of the total global disease burden in 2020

(2)

The treatment for coronary heart disease aims to reduce the risk

of mortality and morbidity as well as to reduce or eliminate

angina pectoris, thus, allowing patients to return to normal

activities. Ideally, these end points should be accomplished with

minimal side effects and adequate long-term results. There are

currently three well-established treatment options for CHD:

medical therapy, coronary artery bypass grafting (CABG), and

percutaneous coronary intervention (PCI). Throughout the last 2

decades, number of clinical trials has been conducted to

compare those strategies. The last two options have been rapidly

evolving. Both techniques have their own strengths and inherent

weaknesses. Each is particularly beneficial in specific clinical

settings. This article aims to review the evidences from the clinical

trials which could provide a fair comparison for medical pro-

fessionals in objectively choosing the best treatment option for

patients with CHD.

Medical Therapy

The primary consideration in choosing pharmacological agents

for treatment of CHD should be to improve prognosis. Aspirin

and lipid-lowering therapy have been proved to reduce the risk

of death and non-fatal myocardial infarction (MI) in both primary

and secondary prevention setting. The data strongly suggest that

cardiac events will also be reduced among patients with chronic

stable angina. The ACC/AHA guidelines suggest that aspirin (75

to 325 mg daily) should be administered routinely to all patients

without contraindications. Clopidogrel can be prescribed in

those having absolute contraindication to aspirin

(1)

. The Choles-

terol and Recurrent Events (CARE) trial and Scandinavian Simvas-

tatin Survival Study (4S) have established the benefit of aggressive

lipid-lowering therapy for most patients with CHD, even when

LDL levels are within the considered acceptable range for

patients in primary prevention setting. In addition, the Medical

Research Council/British Heart Foundation (MRC/BHF) Heart

Protection Study conducted in 20,536 high-risk adults in the

United Kingdom revealed that adding simvastatin 40 mg to

existing treatments reduced the rates of MI, stroke, or revascula-

rization by approximately 24%. Angiotensin-converting enzyme

inhibitors are also recommended for all patients with CHD and

asymptomatic patients with CHD who also have diabetes or left

ventricular systolic dysfunction. The Heart Outcomes Prevention

Evaluation (HOPE) trial confirm that the use of ramipril (10

mg/day) can reduce the composite risk of cardiovascular death,

MI, and stroke by approximately 25% in patients at high risk for

or with current vascular disease without heart failure, regardless

of age, sex, or coexisting disease. On the basis of their beneficial

effects on morbidity and mortality, beta-blockers should be

strongly considered as initial therapy for chronic stable angina, as

secondary prevention in post-MI patients, and as a means to reduce

morbidity and mortality among patients with hypertension.

Long-acting or slow-release calcium antagonists are indicated to

relieve symptoms in patients with chronic stable angina without

enhancing the risk of adverse cardiac events. They are often

preferable than long-acting nitrates for maintenance therapy

due to their sustained effects. Short-acting nitrates do not lose

their effect on symptom relief, but long-acting nitrates may

produce tolerance

(1,3)

Coronary Artery Bypass Grafting

The first CABG to the right coronary artery using a reverse

segment of saphenous vein was performed by Sabiston in 1962.

Although the patient died due to cerebrovascular accident, the

procedure itself was successful. DeBakey performed the first

complete CABG as a bailout procedure after a carotid endar-

terectomy

(4)

. Subsequently, Favaloro in Cleveland Clinic refined

the use of reversed saphenous vein grafts for coronary bypass.

Kolessov and Green were the first who used internal mammary

artery as bypass graft. Subsequently, the number of CABG has

markedly increased. Currently, more than 500,000 operations

are performed in the United States every year with excellent

results

(5)

. Even so, many physicians still attempt to avoid recom-

mending CABG to their patients. This may be in part a result of

the perception that CABG is associated with high mortality risk.

This perception has recently been challenged with large

published studies demonstrating mortality risk of 1.2% to 1.7%

for isolated CABG

(6,7)

. Some limitations of CABG include costs

Current Treatment Options for

Coronary Heart Disease

Yanto Sandy Tjang, Lech Hornik, John Mantas, Richardus Budiman,

Andreas Bairaktaris, Reiner Körfer.

Department of Thoracic & Cardiovascular Surgery,Heart & Diabetes Center

NRW/University Hospital of Bochum,Bad Oeynhausen, Germany

Banyak studi membuktikan bahwa latihan fisik sangat berpengaruh

terhadap kesehatan pembuluh darah dan jantung. Latihan fisik

secara dinamik dan isometrik sama-sama dapat mempengaruhi

tekanan darah. Latihan fisik teratur menghasilkan penurunan

tekana darah yang bermakna dan akan menetap selama latihan

fisik terus dilakukan. Mekanisme perurunan darah tersebut karena

terjadi penurunan curah jantung, penurunan aktivitas sistem

saraf simpatis, penurunan resistensi pembuluh darah perifer dan

meningkatnya sensitivitas baroreflek.

Rujukan : ada pada penulis.

Pada penderita yang lebih tua penurunan tekanan darah juga

berkaitan dengan penurunan resistensi perifer namun individu

dengan curah jantung yang tinggi, mempunyai curah jantung yang

lebih rendah sesudah latihan.

Oleh karena itu umur, lamanya

hipertensi adanya LVH dan barangkali berbagai faktor mempe-

ngaruhi gambaran hemodinamik terhadap penurunan tekanan

darah sesudah latihan. Sirkulasi norepinephrine dan epinephrine

diketahui juga menurun.

41-45,71

Penurunan tekanan darah sesudah

latihan secara ambulatoar sering ditemukan pada saat aktifitas

simpatis relatif tinggi.

Somers dkk

, melaporkan bahwa latihan endurance menurunkan

tekanan darah harian, baik pada saat istirahat maupun pada saat

aktifitas; tetapi tidak menurunkan tekanan darah saat tidur.

Mereka juga melaporkan meningkatnya sensiitivitas barorefleks

dan menurunnya pengaturan untuk meningkatkan tekanan darah

pada peningkatan aktifitas fisik penderita hipertensi ringan

maupun borderline (prahipertensi ).

SIMPULAN

Hipertensi merupakan faktor risiko utama untuk kematian maupun

kesakitan dari penyakit kardiovaskular. Tiga perempat kejadian

kardiovaskular justru terjadi di negara berkembang. Prevalensi

hipertensi makin meningkat karena perubahan definisi hipertensi.

Pengobatan hipertensi sesuai JNC 7 dapat dimulai dari obat anti-

hipertensi semua golongan termasuk antagonis kalsium, penyekat

beta maupun ACE dan ARB.

cdk

.redaksi@

yah

o.co.id

Penyakit Infeksi

Reumatologi

Bedah & Anestesi

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TINJAUAN PUSTAKA

benefit more from initial CABG. They also show that the rates of

repeat revascularization tend to become similar for both strate-

gies on long-term follow-up, probably due to late vein graft

failure in the CABG group. The Stent or Surgery trial has demon-

strated an early survival advantage for CABG

(32)

. This finding is

supported by recent meta-analysis from 13 trials with 7,964

patients

(33)

. When compared with PCI, CABG is associated with

lower 5-year mortality, less angina, and fewer repeat revascular-

izations. CABG provided a survival advantage at 5 - 8 years for

patients with multi-vessel CHD, and at 4 years for diabetic

patients.

The recent development of anti-proliferative DES is a major break-

through in preventing restenosis after initial PCI. DES prevents

neointimal proliferation, thereby, decreasing restenosis and

repeat revascularization. Randomized trials using both sirolimus-and

paclitaxel-eluting stents have shown significant reductions of

repeat revascularization in target lesion. A meta-analysis confirms

these aggregate reductions in repeat revascularization, but it

does not detect any mortality benefit

(34)

. Although several different

drug-eluting stents are under investigation, sirolimus and pacli-

taxel account for the majority of existing clinical data, and are

now commercially available. Clearly, not all of DES is promising.

At least three clinical trials with alternative drug formulations

have been discontinued due to poor effects. The long-term

effects of DES implantation remain unknown. The growing use

of DES not only produces clinical benefits for certain patients, but

also creates financial crises for many health care systems. DES

cost 3 - 7 times higher than their uncoated predecessors.

Conclusion

Despite increased popularity of PCI, CABG remains an important

treatment option for CHD. Further evidence on long-term efficacy

and safety of some DES, especially in high-risk subgroups, is

warranted. Meanwhile, intensive communication between

medical professionals who involve in providing medical care, in

term of objectively choosing the best treatment option for

specified patients with CHD, is of highly necessary. One can be

sure that most of the patients with CHD will benefit from each

treatment options that continue to advance and improve.

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associated with preoperative and postoperative care, the need

for several days of hospitalization (including intensive care),

rehabilitation, and delayed or inability to return to work quickly.

Since the average patency time of venous bypass grafts is around

7 - 10 years; some patients may require repeat revascularization.

In the mid-1990s two new surgical techniques have been intro-

duced in attempts to reduce the invasiveness of the standard

CABG procedure. Revascularization either on an arrested heart

with peripheral cannulation through a small access incision (port

access) or on a beating heart with a limited access approach

(MIDCABG) becomes emerging. However, the lack of demon-

strated benefit and significant technical challenge associated

with the port access approach hamper its widely application.

Similar restriction also happens to MIDCABG procedure since it is

not only technically challenging but also its inability to perform

complete myocardial revascularization. However, the recognition

of improved outcomes in selected patients served as an impetus

to develop off-pump coronary artery bypass (OPCAB) procedure

as a treatment option for patients with multi-vessel CHD. Many

other techniques, such as: complete arterial revascularization,

mechanical anastomosis connector, robotic assist systems, stem

cell implantation and genetic therapy for preventing vein graft

disease are of current research interest.

Percutaneous Coronary Intervention

Werner Forssman inserted a catheter into his own basilic vein

and threaded it to his right atrium for the purpose of «intra-

cardiac drug injection» in 1929. Later on, diagnostic cardiac

catheterization was developed by Cournand, Sones, and Judkins.

In 1964, Dotter and Judkins successfully dilated peripheral

atherosclerotic lesions using progressively larger coaxial dilators.

In 1974, Grüntzig developed the double lumen catheter and

performed the first percutaneous dilation of a human coronary

artery in 1977

(8)

. PCI is considered providing less invasive

approach and offers shorter hospital stay or faster recovery.

During earlier period, the quality of PCI was limited by lack of

user-friendly and lesion-suitable technical equipment. Dissection

and acute or threatened closure result in major morbidity.

Mortality was sufficiently frequent and unpredictable. Therefore,

in many institutions a staffed operating room was always kept

empty for emergeny surgery in case complications exist. The

major limiting factor of PCI is the occurrence of restenosis in

about 3060% of patients, depending on clinical risk factors,

lesion characteristics and technical aspects of the intervention

(9)

Newer interventional techniques such as stents, directional,

rotational, laser atherectomy, thrombectomy devices and drug-

eluting stents (DES) have been introduced into clinical practice

with better results.

Medical Therapy versus CABG

Three large randomized trials

(10-12)

, which included patients with

stable angina and single - or multi - vessel CHD for either medical

or surgical therapy, along with several observational studies and

a meta-analysis

(13)

, have yielded consistent results and established

the role of CABG as a solid treatment option for CHD. CABG

resulted in substantially lower mortality rates at 5-, 7-, and 10-

years compared to medical therapy. Patients with left main

coronary artery disease, three-vessel CHD with impaired left

ventricular function, diabetes mellitus, and instable angina

pectoris derive the greatest benefit from CABG.

Medical Therapy versus PCI

Two randomized clinical trials

(14,15)

, including low-risk patients

who were randomized to either medical therapy or PTCA, have

been published. Mortality rates were similar in both groups.

Patients who underwent PTCA were more likely to be free of

angina. In the Asymptomatic Cardiac Ischemia Pilot trial

(16)

patients with CHD who were free of angina and had evidence of

ischemia on electrocardiography or stress testing were random-

ized to either medical therapy or revascularization (percutaneous

or surgical depending on the operator). Patients who underwent

revascularization had lower mortality, MI, and hospitalization

rates than the medically treated patients. The Medicine, Angio-

plasty or Surgery Study was a three-arm trial that compared

PTCA, medical therapy, and CABG using LIMA graft in patients

with isolated severe proximal LAD stenosis

(17)

. There were no

differences in mortality risk or MI among all three groups.

Patients who underwent CABG or PTCA were more likely to be

symptom-free than those medically treated. Repeat revascular-

izations were higher in the PTCA and medically treated groups.

In the Atorvastatin Versus Revascularization Treatment trial

(18)

low-risk patients who were randomized to aggressive lipid-

lowering therapy with atorvastatin tended to have fewer

ischemic events than those who received angioplasty along with

usual medical care. A recent randomized trial involving 2,287

patients who had objective evidence of MI and significant CHD

at 50 American and Canadian centers demonstrated that PCI did

not reduce the risk of death, MI, or other major cardiovascular

events when added to optimal medical therapy in patients with

stable CHD

(19)

PCI versus CABG

Several randomized trials, comprising more than 5,000 patients,

have compared PCI and CABG in the management of single-

and multi-vessel CHD

(17,20-27)

. Despite differences in design and

inclusion criteria, several conclusions can be drawn from these

trials, in addition to two meta-analyses performed later

(28,29)

There were no significant differences in mortality or combined

endpoint of death and non-fatal MI between PCI and CABG.

Patients undergoing initial PCI are more likely to require repeat

revascularization (either CABG or PCI) than patients undergoing

initial CABG. Initial costs are lower in the PCI group but tend to

equalize later, owing to the increased repeat revascularizations.

More importantly, patients with treated diabetes mellitus seem

to have better survival from initial CABG than PCI. Recent long-

term follow-up results have been published

(30,31)

. More recent

data emphasize previous findings and confirm the similar survival

achieved by both strategies, except in the diabetic patients who