Page 624 - Cardiac Nursing

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600 PA R T I V / Pathophysiology and Management of Heart Disease
Operative Results for MIDCAB and OPCAB surgical repair of valves is similar to that of the patient after
Midterm results in patients undergoing MIDCAB through left CABG surgery.
anterior small thoracotomy and using the left IMA and OPCAB
have been encouraging. In a multicenter, randomized controlled Valvular Replacement
trial comparing OPCAB and CABG with CPB, 20 the OPCAB If a dysfunctional mitral or aortic valve is not suitable for repair,
group had less use of blood products (p 0.01) and 41% less valve replacement is undertaken. Valvular heart surgery can be ac-
(
release of creatinine kinase (CK; p 0.01), but otherwise there complished through a standard median sternotomy incision,
were no significant differences in complications, quality of life, through a small parasternal incision, or through port access using
length of stay, or recurrent angina. A prospective randomized small incisions and endoscopic techniques. Because valve surgery
trial was conducted by Drenth et al. 21 comparing coronary ar- requires an arrested, open heart, CPB must be used and can be
tery percutaneous transluminal coronary angioplasty with stent- done by the standard method or by femorofemoral cannulation.
ing (PCI) to OPCAB in patients for high-grade proximal LAD Surgical techniques for mitral valve replacement (MVR) and aor-
lesions. In a mean follow-up time of 3 years, angina pectoris tic valve replacement (AVR), types of prosthetic heart valves, and
class was lower in the OPCAB group (p 0.02) as well as the indications for valvular replacement are discussed in Chapter 29.
(
need for antianginal medication (p 0.01) when compared to
(
the PCI group. OPCAB is technically more difficult and de- Mitral Valve Repair or Replacement. The routine medical
manding for surgeons. 22 Because operative techniques that in- care after MVR surgery is similar to that after CABG surgery.
volve minimally invasive incisions, port access, and operation on Early after MVR surgery, a patient is more likely to have impor-
a beating heart have a learning curve, results associated with this tant cardiovascular or pulmonary dysfunction than a patient who
newer operative technology are expected to continue to improve has undergone CABG surgery. Late after surgery, problems related
over time. to the prosthetic device may occur. Prognosis and outcome after
MVR are related to severity of the left ventricular and right ven-
tricular dysfunction before surgery.
Transmyocardial Laser
Revascularization Aortic Valve Replacement. The routine medical care after
AVR surgery is similar to that after CABG surgery. Early after
Transmyocardial laser revascularization (TMLR or TMR) is a AVR surgery, a patient is more likely to have arrhythmia, de-
technique under investigation in patients with refractory angina. creased cardiac output, or neurologic dysfunction than a patient
In TMLR, carbon dioxide, holmium-YAG (yttrium–aluminum who has undergone CABG surgery. Late after surgery, arrhythmia,
garnet), or excimer lasers 23 are used to produce multiple channels heart failure, or problems related to the prosthetic device may oc-
from the endocardial surface of the ventricular wall in an effort di- cur. Prognosis and outcome after AVR are related to severity of left
rectly to improve blood flow to areas of myocardium that cannot ventricular dysfunction before surgery.
be revascularized using traditional techniques. It has also been
postulated that myocardial blood flow is enhanced by angiogene-
sis that occurs with TMLR, although this is still unproven. Left Surgical Techniques for the
anterolateral thoracotomy is most often used to provide exposure, Failing Heart
although TMLR can also be done by standard median sternotomy
if it is performed at the same time as standard CABG to other ves- As an alternative to cardiac transplant, number surgical tech-
sels. TMLR is done on a beating heart. The laser is synchronized niques are evolving. In the Dor procedure, the left ventricular cav-
with the patient’s R-wave. Transesophageal echocardiography is ity is opened and monofilament sutures placed circumferentially
used to detect steam or bubbles that verify channel creation. Epi- above the boarder of the diseased muscle, restoring the normal
25
cardial surface seals off with gentle pressure, leaving an endocar- contour of the ventricle. The reduction ventriculoplasty was pi-
dial channel in which blood flows. TMLR is recognized by the So- oneered by Batitista as a surgical option for patients with car-
ciety of Thoracic Surgery as acceptable as either sole therapy or as diomyopathy who cannot undergo cardiac transplantation. To de-
an adjunct to a selected subset of patients with refractory angina crease wall tension and ventricular size in the dilated left
be cannot be revascularized by the more traditional methods of ventricular, an oval-shaped portion of myocardium is removed
bypass surgery or percutaneous intervention. 24 from apex to base. Although Batitista reported encouraging results
in his own series, this procedure after being introduced in the
25
United States has had mixed results. While the Cleveland Clinic
series reported midterm results with a 30-day mortality rate of
CARDIAC SURGERY 3.2%, other series have reported high mortality rates. 25
26
PROCEDURES FOR ACQUIRED Dynamic cardiomyoplasty is an alternative to heart transplan-
STRUCTURAL HEART DISEASE tation for patients with end-stage heart failure. Surgery is accom-
plished through a left thoracotomy incision, and CPB is not re-
Acquired Valvular Heart Disease quired. The latissimus dorsi muscle is placed into the thoracic
cavity through a space where the second rib has been resected. In-
Valvular Repair tramuscular pacing electrodes are inserted in the proximal portion
Surgical repair of a stenotic or incompetent mitral valve is per- of the muscle. The patient is then repositioned, and a sternal in-
formed frequently. The reparative surgeries, mitral commissuro- cision is made to complete the muscle wrap around the heart. A
tomy (in which the fused valve cusps are split open) and annulo- cardiomyostimulator (a pacemaker especially designed for car-
plasty (in which the large orifice of an incompetent valve is made diomyoplasty) is implanted beneath the rectus muscle and acti-
smaller) are discussed in Chapter 29. Care of the patient after vated 2 weeks after surgery, allowing the muscle to rest and