Uji diagnostik pemeriksaan massa Creatine Kinase-MB untuk infark miokard akut

FAIKA, Rosni, dr. Osman Sianipar, DMM.,M.Sc.,SpPK(K)

2007 | Tesis | PPDS I Patologi Klinik

Selama lebih dari 3 dekade infark miokard akut (IMA) masih terus menjadi masalah kesehatan masyarakat yang utama pada negara maju dan makin meningkat pada negara berkembang. Pengenalan dini terhadap tanda dan gejala, diagnosis yang akurat serta terapi yang tepat waktu sangat diperlukan untuk membatasi luasnya infark, memelihara fungsi miokardium dan menurunkan angka kematian. Petanda jantung tradisional seperti aktivitas CK-MB diketahui mempunyai sensitivitas dan spesifisitas yang rendah untuk diagnosis IMA. Berbeda dengan CK-MB konvensional yang mengukur aktivitas enzim secara tidak langsung, pada massa CK-MB dilakukan pengukuran secara langsung terhadap konsentrasi enzim. Tujuan penelitian ini adalah menguji penampilan diagnosis massa CK-MB serta menentukan nilai cutoff massa CK-MB untuk diagnosis IMA. Penelitian ini menggunakan rancangan uji diagnostik dengan kriteria WHO sebagai metode rujukan untuk IMA. Subyek penelitian adalah pasien nyeri dada yang datang di Instalasi Rawat Darurat (IRD) RSUP Dr. Sardjito Yogyakarta. Interval waktu antara timbulnya nyeri dada sampai pasien datang di IRD dicatat. Pemeriksaan massa CK-MB dilakukan pada sampel darah yang sama dengan sampel untuk pemeriksaan aktivitas CK-MB yang diambil saat pasien datang di IRD. Diagnosis IMA diperoleh dengan melakukan penelusuran terhadap rekam medik pasien. Sensitivitas, spesifisitas, nilai ramal positif (NRP), nilai ramal negatif (NRN), akurasi, dan likelihood ratio (LR) dihitung dengan tabel 2x2. Analisis kurva ROC dilakukan menggunakan program SPSS 11.0. Penelitian dilakukan pada 66 subyek, 49 diantaranya dengan diagnosis IMA. Pada kadar 5 ng/mL, tanpa memperhitungkan waktu antara onset penyakit dan saat pasien datang ke rumah sakit, massa CK-MB menunjukkan sensitivitas dan spesifisitas masing-masing 65% dan 82%. Massa CK-MB memberikan penampilan diagnosis terbaik pada interval waktu >4 – 24 jam setelah onset, dengan sensitivitas 95%, spesifisitas 82%, NRP 91%, NRN 90%, akurasi 91%, LR+ 5,3 dan LR- 0,1.

Despite impressive strides in diagnosis and management over the past three decades, acute myocardial infarction (AMI) continues to be a major public health problem in the industrialized world and is becoming an increasingly important problem in developing countries. Prompt recognition of signs and symptoms, accurate diagnosis, and timely treatment are essential to limit the size of the infarct, preserve myocardial function, and reduce mortality. Traditional marker such CK-MB activity have low sensitivity and specificity in the diagnosis AMI. Creatine Kinase-MB (CK-MB) mass differ from conventional CK-MB measurement in that latter is an indirect measurement of the enzyme activity, while CK-MB mass is a direct measurement of the enzyme concentration. This study is to investigate the clinical performance of CK-MB mass and assess the cutoff point in the diagnosis AMI. The study design is a diagnostic test with the WHO diagnostic criteria of acute myocardial infarction as the reference method. This study include patients who presented to the Emergency Department at Dr. Sardjito General Hospital with chest pain. The interval between the onset of the symptoms and admission is noted. Blood samples are obtained at admission. The diagnosis of AMI is obtained from inspection of medical record for each patients. The clinical sensitivity, specificity, positive and negative predictive value, accuracy and likelihood ratios are calculated by 2x2 tables. Receiver Operating Characteristics (ROC) analysis is performed using SPSS 11.0. Forty-nine of sixty-six subject are from AMI patients. At 5 ng/mL as a cutoff point, regardless the interval between the onset of the symptoms and admitted to hospital, the sensitivity and specificity are 65% and 82%, respectively. The best diagnostic performance of the CK-MB mass are found in interval >4-24 hour with the sensitivity, specificity, positive and negative predictive value, and accuracy results are 95%, 82%, 91%, 90%, 91%, respectively. Likelihood ratios for positive and negative results are 5,3 and 0,1, respectively.

Kata Kunci : Infark Miokard Akut,Uji Diagnostik,Massa Creatine Kinase,MB, acute myocardial infarction, CK-MB mass, diagnostic test