Diagnostic Tests for the CV System PDF

Diagnostic Tests for the CV System Arranged by Dr. Kim Stiles, PhD, RN, CNE, AHN-BC Diagnostic Studies of Cardiovascular System: Labs Cardiac Biomarkers—injured cells release enzymes and proteins into blood; consider time from onset of symptoms of ACS Troponin Troponin I or Troponin T Rises within 4...

Diagnostic Tests for the CV System Arranged by Dr. Kim Stiles, PhD, RN, CNE, AHN-BC Diagnostic Studies of Cardiovascular System: Labs Cardiac Biomarkers—injured cells release enzymes and proteins into blood; consider time from onset of symptoms of ACS Troponin Troponin I or Troponin T Rises within 4 to 6 hours, peaks 10 to 24 hours, detected for up to 10 to 14 days High-sensitivity troponin (hs-cTnT, hs-cTnI) assays may detect a heart injury within 1-3 hours Creatine kinase (CK); 3 isoenzymes CK-MB cardiac specific; increased with MI or cardiac injury Rises in 3 to 6 hours, peaks in 12 to 24 hours, returns to baseline within 12 to 48 hours Rarely used for diagnosis of acute MI 2 Diagnostic Studies of Cardiovascular System: Labs Additional blood studies Cardiac natriuretic peptide markers Three types Atrial natriuretic peptide (ANP) B-type natriuretic peptide (BNP)—heart failure C-type natriuretic peptide Increased levels of BNP distinguishes cardiac vs respiratory cause of dyspnea NT-pro-BNP Increased DBP leads to release of BNP and NT-pro-BNP leads to increased urinary excretion of Na+ 3 Diagnostic Studies of Cardiovascular System: Labs Additional blood studies C-reactive protein (CRP) Marker for inflammation Linked to atherosclerosis and first heart event; predict risk of future heart events Homocysteine (Hcy)—protein catabolism Hereditary or dietary deficiency of vitamins B6, B12, or folate High levels—increased risk for CVD, PVD, stroke 4 Diagnostic Studies of Cardiovascular System: Labs Serum lipids “lipid panel” Triglycerides—storage form of lipids Cholesterol—absorbed from food and made in liver Phospholipids—glycerol, fatty acids, phosphates, and nitrogenous compound Four classes of lipoproteins (serum lipids that bind to protein to circulate in blood) Chylomicrons Low-density lipoproteins (LDLs) High-density lipoproteins (HDLs) Very-low-density lipoproteins (VLDLs) Increased Triglycerides and LDL—CAD risk factor Increased HDL decreases risk—decreased risk of CAD Cholesterol: HDL ratio—risk assessment 5 Audience Response Question A patient arrives at an urgent care center after experiencing unrelenting substernal and epigastric pain and pressure for about 12 hours. The nurse reviews laboratory results with the understanding that at this point in time, a myocardial infarction would by indicated by peak levels of: a. troponin T. b. homocysteine. c. creatine kinase-MB. d. type b natriuretic peptide. 6 Diagnostic Studies of Cardiovascular System: ECG Electrocardiogram Resting 12 lead ECG Ambulatory ECG monitoring (Holter) Exercise or stress testing Event monitor or loop recorder External—electrodes worn for a month; activated by patient when symptoms occur (may be over before recorded) Internal—serious, infrequent dysrhythmias; continuous monitor when symptoms occur or when HR increases or decreases from set rate 7 12 Lead ECG: NSR Diagnostic Studies of Cardiovascular System: Stress testing Functional studies Exercise or stress testing Heart symptoms with activity—Increased O2 demand Assess CVD; set limits for exercise Patients walk or ride bike while ECG and BP monitored 6-minute walk test—general fitness Flat surface; baseline response to treatment and PT Noninvasive hemodynamic monitoring Monitors SV, CO, and BP by finger cuff or thoracic bioreactance; used during complex surgery 9 Diagnostic Studies of Cardiovascular System: CXR Imaging Chest x-ray Heart displaced or enlarged Pericardial effusion Pulmonary congestion 10 Diagnostic Studies of Cardiovascular System: Echo Echocardiogram Ultrasound waves record movement of heart structures; with or without contrast Determines abnormalities of: Valve structures and motion Heart chamber size and contents Ventricular and septal motion and thickness Pericardial sac Ascending aorta Measures ejection fraction (EF)—% of end-diastolic blood volume ejected during systole. Normal range is 60-70%. 11 Diagnostic Studies of Cardiovascular System: Echo Echocardiogram Motion made (M-mode) Motion, wall thickness, and chamber size Two-dimensional (2-D) Spatial relationship of structures Doppler technology → Sound evaluation of flow or motion of scanned object Color-flow imaging (duplex) → Combination of 2-D and Doppler— show speed and direction of blood flow 12 Diagnostic Studies of Cardiovascular System: Echo Echocardiogram Real time 3-D How structures change during cardiac cycle Stress echocardiography Computer compares images or wall motion and function before and after exercise No exercise—use IV dobutamine and dipyridamole for pharmacologic stress Bubble study Contrast echocardiography checks for defects in wall between the two upper chambers of the heart 13 Diagnostic Studies of Cardiovascular System: TEE Echocardiogram Transesophageal echocardiography (TEE) Better visualization of heart with endoscope Requires NPO, sedation; check gag afterward Evaluates: mitral valve disease, endocarditis vegetation, thrombus before cardioversion, source of heart emboli, intraoperative heart function, and aortic dissection Complications: perforation of esophagus, hemorrhage, dysrhythmias, vasovagal reactions, transient hypoxemia Used for extremely obese people who can’t have other tests done because of equipment limitations 14 Diagnostic Studies of Cardiovascular System: CT scan Tomography Cardiac computed tomography Heart anatomy, coronary circulation, great vessels (multidetector CT scanning— MDCT) CT angiography (CTA) Noninvasive; faster, less risky, less radiation exposure than cardiac catheterization; must have NSR Calcium-scoring screening Identifies calcium deposits in coronary arteries Confirms suspected CAD; predict future cardiac events Electron beam CT (EBCT) 15 Calcium Scoring CT scan 16 Diagnostic Studies of Cardiovascular System: MRI Cardiovascular magnetic resonance imaging (CMRI)—no radiation 3-D view of MI; assess EF Predicts recovery from MI Diagnosis of congenital heart and aortic disorders and CAD Patients with stents can undergo CMRI 6 weeks after placement 17 Diagnostic Studies of Cardiovascular System: MUGA Nuclear cardiology Multigated acquisition—MUGA scan Wall motion, heart valves, EF Stress perfusion imaging Blood flow changes with exercise diagnoses CAD Viable heart tissue versus scar tissue Determine success of interventions (e.g., CABG or PCI) IV medications to dilate coronary arteries and simulate exercise effects SPECT—size of infarction PET stress testing—myocardial ischemia and viability 18 Diagnostic Studies of Cardiovascular System: IVUS & EPS Intravascular ultrasound (IVUS) Intracoronary ultrasound (ICUS); done in cath lab Also uses coronary angiography to provide a 2-D or 3-D view of the coronary artery walls Evaluate vessel response to stent placement and atherectomy Electrophysiology study (EPS) Electrodes placed in heart to record and manipulate electrical activity of heart; SA node, AV node, and ventricular conduction—information regarding source and treatment of tachydysrhythmias Nursing care—similar to cardiac catheterization where: 1. 2. 3. 4. 5. Access Femoral Artery Catheter advanced through Aorta into the coronary ostia and to coronary arteries Contrast is injected Coronaries are visualized LV function is assessed 19 Diagnostic Studies of Cardiovascular System: Cardiac Catheterization Interventional studies Cardiac catheterization—contrast and fluoroscopy CAD, coronary spasm, congenital and valvular heart disease, ventricular function, intracardiac pressures and O2 levels, CO, and EF Right-sided to measure pressures from vena cava to pulmonary artery Left-sided—arterial insertion to evaluate coronary arteries; coronary angiography (dye injected) to identify location and severity of blockages Complications: bleeding or hematoma at puncture site; allergic reaction to contrast; looping or kinking of catheter; infection; thrombus formation; aortic dissection; dysrhythmias; MI; stroke; puncture of ventricles, coronary arteries, septum, or lung tissue 20 PCI – Interventional Cardiology Angioplasty Stenting Balloon is inflated Pushes plaque against the wall. Wire mesh coil is expanded against the wall of the vessel to prevent closure. Athrectomy/Rotoblator Uses a cutting device to remove plaque from the artery wall. Nursing Management pre cardiac cath Nursing Management of the Patient Undergoing Cardiac Catheterization Preprocedure: Assess allergies; contrast dye Baseline assessment: VS, pulse oximetry, heart and breath sounds, neurovascular assessment of extremities, mark pedal pulses NPO for 6 to 12 hours Assess labs Patient education: Procedure—local anesthesia, flushed feeling when dye injected; fluttering of heart Administer sedation and other meds as ordered 22 Nursing Management post cardiac cath Postprocedure Baseline Assessment: compare to preprocedure, assess Neuro, LS, and LE for edema, why? Assess pedal pulses! Compression device over arterial site for hemostasis; observe for hematoma and bleeding every 15 minutes for 1 hour then per agency policy; bed rest as ordered If femoral access done, no bending of hips for some time afterwards depending on closure device (Reverse Trendelenberg position) Monitor: ECG, chest pain, IV/oral fluid intake and urine output Patient Education: discharge instructions, activity limits 23 What’s coming next: Coronary Computed Tomography Angiography “Cleerly” process FDA approved to evaluate and stage plaque (soft vs. hard type of plaque) in people BEFORE they have any S/S CV disease. 50% of MI’s happen without warning signs. Medicare will reimburse $950. Still not approved by all insurance companies. Intravascular Lithotripsy: FDA approved 2021. Uses shock waves to break up hard plaques, thus enabling stent placement in adults older than 60. PCSK9 Inhibitors: injection every 3-6 months to reduce LDL by 50-60%. Good for those who can’t tolerate statins, reduces MI by 15-20% more than statins used alone.