The future of minimallyinvasive cardiac surgery

Coronary artery bypass graft (CABG) has been the preferredstandard of surgical treatment for coronary artery disease sincethe early 1970s. Over the years, refinements in intubation,cardioplegia, and extracorporeal circulation have improved itsoverall success rate to approximately 99%.1 Less invasive andtraumatic forms of heart surgery have rapidly increased, andhave led to several minimally invasive heart surgery procedures.While current research hasn’t been able to identify which pro-cedure is best, many new options are available for patients withcoronary heart disease.

Preoperative phaseThe phase of surgery is a time of great stress and anxiety. Thefear of pain, anesthesia, and death are frightening to bothpatients and their loved ones, and in most cases, go unspokento healthcare professionals. It’s important to assess the patientand family for stress-associated disorders using concepts fromcrisis intervention. Treating the patient and his or her family ina holistic manner is crucial during this period.

The nurse should assure that required forms, such as the sur-gical consent, history and physical examination, and preproce-dure/preoperative surgical checklist, are complete and signed.The results of preprocedure laboratory tests should be availablein the medical record. Any values outside of the normal rangeshould be brought to the physician’s attention. In addition, thenurse should be able to answer questions posed by the patientor family members. Patient and family education is geared tothe next immediate steps in patient care, and should includecrucial information needed during this highly stressful period.

The family also requires support during this time, with thefocus being placed on anxiety management and the compe-tence of the surgical staff. Open, honest, and timely communi-cation with the family regarding the patient’s condition iscomforting, and provides a good opportunity for the healthcareteam to assess the family’s ability to learn and process infor-mation. This family communication not only helps to decrease

By Victoria A. Kark, RN, CCNS, CCRN, MSN

2.0ANCC/AACN

CONTACT HOURS

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misunderstandings, but fosters atrusting relationship.

While the family is waitingfor their loved one, basic com-forts such as a nearby waitingroom, a place to rest for familymembers who themselves aren’tin the best of health, andrestroom facilities that are con-venient to the area are neces-sary. Moreover, the familyshould be encouraged to shareany information that mightassist with caring for the patientperioperatively.

During the preoperativephase, basic needs such as theright to privacy, relief from painor anxiety, and safety issues areparamount. The use of relax-ation techniques such as guidedimagery, meditation, and prayerhave been incorporated bymany cardiac surgery programswith great success and positivepatient satisfaction results.2

Surgery overviewCABG decreases the overall mor-tality of coronary heart disease,improves the functional status ofpatients, and provides relief fromangina. Many patients report animprovement in quality of lifebecause of a decreased need forpharmacologic therapy, and areduction in the frequency ofinterventional procedures.CABGs experience a patencyrate on average of 20 years(see Coronary artery bypass grafts).

Indications for CABG werefirst defined by the results ofthe Coronary Artery SurgeryStudy (CASS).3 The study wasperformed by cardiothoracicsurgeons and cardiologists in theearly days of bypass surgery.Results demonstrated a survivaladvantage for patients undergo-ing surgery who had disease ofthe left main coronary artery,disease of all three major coro-

nary arteries, and patients withleft ventricular dysfunction.3

In general, cardiac surgery isindicated for patients who havesignificant stenosis of the leftmain coronary artery, severeanginal symptoms unrespon-sive to all other therapies, andstenoses in three coronary arter-ies with an ejection fraction ofless than 50%.4 Patients who failpercutaneous coronary interven-tion (PCI) or those with lesionsthat are too numerous or inac-cessible to revascularizationwith PCI are also appropriatecandidates. Other indicationsinclude younger patients whohave small coronary arteriesand need several bypasses, orpatients whose heart won’t tol-erate being manipulated duringthe procedure. Coronary arterybypass grafting performed on abeating heart is still consideredtechnically more difficult thansurgery on a nonbeating heart.

Advantages anddisadvantagesTraditional or conventional CABGsurgery is performed with theassistance of cardiopulmonarybypass (CPB). (See Cardiopulmonarybypass (CPB) system.) Over the last50 years, extracorporeal circula-tion has evolved into a safe meansof providing systemic perfusionduring open heart surgery. CPBmay be of particular advantagefor patients with heart failure,cardiomegaly, or acute myocardialinfarction. Patients who havecoronary arteries that are moretechnically difficult to bypass orhave an inaccessible location,particularly on the posterior sur-face of the heart, are also goodcandidates. CPB diverts bloodfrom the heart, removes carbon

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The future of minimally invasive cardiac surgery

Coronary artery bypass grafts12

One or more procedures may be performed using various veins andarteries. (A) Left internal mammary artery, used frequently because ofits functional longevity. (B) Saphenous vein, also used as bypass graft.

dioxide from the blood, oxy-genates it, and returns it to thebody. Cardioplegia is instilled intothe coronary circulation, whichcauses cardiac arrest so that thesurgeon can operate on a motion-less and blood free surgical field.4

While traditional CABG surgeryusing extracorporeal bypass hasmany benefits, it isn’t withoutcomplications. Negative outcomesof the procedure fall into distinctmajor categories, including car-diovascular, hematologic, renal,pulmonary, and neurologic insult.One of the most significant com-

plications is the inability to weanthe patient from CPB. This isregarded as one of the more com-plicated sequences during cardiacsurgery, since the patient’s heartmust resume responsibility forelectrical as well as mechanicalactivity. Assist devices such asthe intra-aortic balloon pump ora ventricular assist device may beemployed if the patient experi-ences cardiac failure or an inabilityto wean from CPB. Dysrhythmiasmay also be a common complica-tion during this process andcan be treated either through

pharmacologic or electricaltherapy, such as defibrillationor synchronized electrical car-dioversion, depending on thepatient’s cardiac rhythm andhemodynamic status.

Investigators have examinedCABG’s effect on the coagulationand complement cascades, whichare affected when the patient’sblood comes into contact with theextracorporeal circuit of CPB.5

Common hematologic complica-tions after bypass include hemo-dilution, hemolysis, and decreasedcoagulation factors, which result

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Cardiopulmonary bypass (CPB) system12

The cardiopulmonary bypass (CPB) system, in which cannulas are placed through the right atrium into thesuperior and inferior vena cavae to divert blood from the body and into the bypass system. The pump sys-tem creates a vacuum, pulling blood into the venous reservoir. The blood is cleared of air bubbles, clots,and particulates by the filter and then is passed through the oxygenator, releasing carbon dioxide andobtaining oxygen. Next, the blood is pulled to the pump and pushed out to the heat exchanger, where itstemperature is regulated. The blood is then returned to the body via the ascending aorta.

in the necessity for blood trans-fusion. Patients with longer CPBruns can experience more delete-rious effects including compro-mise of the immune system,which may lead to multisystemorgan failure.

Pulmonary complications ofCPB result from hypoventilation,accumulation of extravascularfluid, and decreased surfactant,which contributes to atelectasis.Postoperative respiratory compli-cations can range from atelec-tasis and pneumonia to acuterespiratory failure.

A major complication post-CPBis acute renal failure (ARF), whichoccurs in 7% to 8% of patients.4

Older adult patients are most like-ly to experience ARF, especially ifthey have low cardiac output,oliguria, or renal dysfunctionpreoperatively. Patients withborderline renal function priorto surgery may require short-termdialysis postoperatively untilrenal function is restored.

Short-term neurologic changesinclude memory loss, difficultythinking clearly, and problemsconcentrating for lengthy periodsof time. Recent research hasraised the question of whetherthese short-term changes mayaffect long-term cognitive func-tion.6 The reason for cognitivedeficits isn’t definitely known,but may be related to microem-boli released from atheroscleroticplaque or blood transfusions. It’salso been attributed to the CPBmachine and its effects. Theemboli may affect the brain,resulting in cognitive dysfunction.6

Other neurologic complicationsthat may occur range from swal-lowing deficits to global strokeand death, which has an occur-rence rate of approximately 8%.7

Despite these complications,upwards of 50% of CABG proce-dures performed at most of the900 cardiac surgery centers in theUnited States use CPB.

Many surgeons choose thistraditional technique because ofthe intense debate as to com-pleteness of revascularizationwith minimally invasive surg-eries. The decision to perform aprocedure on or off CPB is oftenmade during the procedure itselfas the surgeon evaluates thepatient’s progress and adequacyof perfusion.

Intraoperative phaseNursing care during the intraop-erative phase of cardiac surgeryfocuses extensively on the peri-operative nurse acting as apatient advocate during a timewhen the patient is most vulner-able. Patient safety issues thatcreate and maintain safe-careenvironments are the periopera-tive nurse’s immediate responsi-bility, and may include activitiessuch as correct patient identifi-

cation for the surgical procedureand medication administration,preparation of specimens, andblood transfusions. Continuousmonitoring of the patient duringthe procedure is the surgicalteam’s responsibility, with theperioperative nurse assumingresponsibility for many aspectsof care. The proper positioningof the patient to prevent injuries,communication of informationto the members of the health-care team, and the documenta-tion of care, medications, andtreatments must be completed.Providing emotional support tothe family, depending on thehospital’s protocol for familyupdates, keeps family membersinformed as to the patient’s con-dition and the progress of thesurgical procedure. Emergenciesthat arise in the OR, such as car-diac arrest during induction orfailure to come off bypass, arecomplications that require extra-ordinary rapid sequence activi-ties that become routine formost programs as they developexpertise with cardiac surgeryemergencies.

Much like the preoperativephase, the intraoperative phaseis an anxiety-producing situationfor family members. Researchsuggests that intraoperativeprogress reports are beneficialto assisting the family in control-ling their anxiety and increasingfamily members’ sense of control.8

Decreasing the stress associatedwith the intraoperative period canpositively affect the family’s abilityto respond to education, and mayalso significantly impact patientoutcomes. Communication mayoccur in the form of telephoneupdates or in-person reportsfollowing a standard protocol.

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The future of minimally invasive cardiac surgery

CABG decreasesthe overall mortality

of coronary heartdisease, improves thefunctional status of

patients, and providesrelief from angina.

Surgical approachesThe first efforts to alter the surgi-cal approach from median ster-notomy to smaller, less traumaticincisions began in the mid-1990s.Starting with initial attempts atCABG surgery through limitedaccess with and without robotics,a number of cardiac procedureswere developed and are currentlybeing performed by minimallyinvasive approaches. These tech-niques not only alter the surgicalapproach, but whether the patientis placed on or off CPB. Off-pumpcoronary artery bypass (OPCAB),robotic-assisted coronary arterybypass (RACAB), and totallyendoscopic coronary arterybypass (TECAB) using Heartportare some of the minimally inva-sive approaches currently avail-able. In addition to CABG, mini-mally invasive approaches maybe used with mitral valve repair,transapical aortic valve implanta-tion, endoscopic pulmonary veinisolation for the treatment of atri-al fibrillation, and the treatmentof aortic aneurysmal disease bythoracic endografting.

OPCAB offers certain advan-tages in low-risk patient popula-tions, such as decreased cost;reduced length of stay; reducedpostoperative complications,such as psychomotor and cogni-tive deficits; and avoidance ofblood transfusions. It alsoreduces surgical trauma to thepatient, as well as stroke andkidney failure. In older adult,high-risk patients, minimallyinvasive cardiac surgery mayreduce the risk of stroke, renalfailure, prolonged respiratoryassistance, and, perhaps death.4

While select research demon-strates reduced risks from mini-mally invasive procedures, most

studies show complicationsinvolving the renal, neurologic,hematologic, and cardiac systems,which are similarly experiencedin traditional CABG surgery.5 Anadditional complication may bethe inability to completely revas-cularize the heart, leaving signifi-cant lesions untreated due to theirlocation. Conversion to a fullsternotomy or CPB is expectedin approximately 1% to 2% ofpatients. Other patients experi-ence complications involving ribfractures at a rate of 10%.5

Minimally invasive directCABG procedures may be limit-ed to a set of patients requiringonly one to two bypasses in oneor two coronary arteries locatedon the anterior surface of theheart. Often the patient is con-sidered too high of a risk for tra-ditional bypass surgery. Althoughminimally invasive proceduresare usually associated with lowmortality, patients may experi-ence a myriad of postoperativecomplications.

Despite the differences inpatient selection and treatmentstrategy, research doesn’t demon-strate any significant survivaladvantage for patients havingOPCAB in comparison with con-ventional CABG. However, oneof the primary goals of OPCAB isto decrease the morbidity ofCABG by less invasive andtraumatic techniques. OPCABsurgery differs from traditionalcoronary artery bypass surgerybecause the CPB system isn’tused. Because of this, the heartisn’t arrested with cardioplegia,but is held in place by mechani-cal stabilizers and positioningdevices during the procedure.(See Stabilizer device for off-pumpcoronary artery bypass surgery.)

An apical suction device isplaced on the apex of the leftventricle to manipulate theheart and expose the differentcoronary arteries. The surgeonbypasses the targeted coronaryartery while the rest of the heartkeeps pumping and circulating

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Stabilizer device for off-pump coronary arterybypass surgery

blood to the rest of the body. Ingeneral, the types of patients withcoronary artery disease who arecandidates for OPCAB includethose with very low ejection frac-tions, severe lung disease, acuteor chronic kidney failure, highrisk for stroke, and calcifiedaorta.5 Conversion to CPB maybe required if the patient can’tbe revascularized due to hemody-namic instability, refractory dys-rhythmias, significant ischemia,poor anastomosis, or poor surgicalsite access.

Technological advancesAdvances in video imaging,endoscope technology, andinstrumentation have made itpossible to convert some surgicalprocedures from open surgeriesto endoscopic ones. For example,CABG surgery is achievableusing a computerized roboticsteam. Through one port, a tiny,high-powered, voice-operatedcamera or endoscope is insertedand stabilized with a roboticarm. Two robotic arms controlthe surgical equipment that’sinserted in the other ports. Thesurgeon makes a small incisioninto the chest and then operatesthe robotic arms to perform theprocedure. Advantages for thistype of procedure are the mini-mal incisions, the absence of aCPB system, and the precisemovements that are beyondthe ability of the human eye.

Surgeons were once wary ofthe time and training that robot-ics required.9 Future researchwill focus on delivery of diagnos-tic and therapeutic modalitiesunder remote control and naviga-tion that could make noninvasivesurgery a reality. One drawback,however, is that RACAB still isn’t

readily available at most cardiacsurgery centers.

TECAB surgery usingport accessPort-access cardiac surgery(PACS), begun in 1995, has alearning curve that’s a challengefor the skilled and experiencedcardiac surgeon. This type ofminimally invasive surgery isn’tonly technically difficult, butrequires specialized expertisefrom anesthesiologists and sur-geons and increases OR utiliza-tion. Anesthesiologists must beproficient in transesophagealechocardiography to guide prop-er placement of the coronarysinus catheter, pulmonary arterycatheter, venous drainage cannula,and endoaortic balloon catheter.The proposed advantages ofPACS include less postoperativepain, decreased hospitalizationand rehabilitation periods, andreduced healthcare costs, whichremain unsubstantiated by prop-

erly designed prospective inves-tigational research studies. PACSis associated with unique chal-lenges and potentially lethalrisks, such as aortic dissection,aortic valve trauma, coronarysinus trauma, and right ventric-ular rupture.10 These risksaren’t commonly associatedwith conventional cardiacsurgery. Proper placement of adouble-lumen endotracheal tubewith one-lung ventilation isrequired. An anterior medi-astinotomy and thoracic port inconjunction with a speciallydesigned set of endovascularcatheters is also used. Thesecatheters, and the use of a modi-fied CPB system, provide com-plete cardiopulmonary support.Surgeons must operate throughsmall incisions, and the qualityof the surgical results may besuboptimal. The benefits ofTECAB include reduction ofsurgical trauma, smaller surgicalincision, and in some cases theelimination of CPB. The survivalrate is reported in some articlesas 99%, with an incidence ofperioperative stroke of 1% andan aortic dissection rate of 1%.10

Other complications are notedto be similar to comparableminimally invasive techniques.

Postoperative phaseThe perioperative nurse’s role isoften complete once the patient istransferred to the critical carerecovery unit. The handoff proce-dure, a current Joint Commissionfocus, allows for continuity ofcare for the patient and his or herfamily, and is established by hos-pital protocol. In some institu-tions, the perioperative nursemay complete a follow-up visit toassess the patient and family’s

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The future of minimally invasive cardiac surgery

Advances in videoimaging, endoscope

technology, andinstrumentation havemade it possible to

convert some surgicalprocedures fromopen surgeries toendoscopic ones.

satisfaction with the operativeexperience. This is often doneon the second or third day post-operatively, and may follow astandard protocol.

The National Heart, Lung, andBlood Institute Working Grouphas determined that future direc-tions in cardiac surgery mustsupport a large, multicenter, ran-domized, clinical trial to compareOPCAB surgery with traditionalsurgery. Research emphasisshould also focus on computer-enhanced imaging, instrumenta-tion, and robotics. Some of thebarriers to clinical research mustbe addressed so that patientsreceive the highest quality ofcare that can be provided.

More than 910,000 Americansdie of heart disease each year inthe United States. Approximately70 million Americans live everyday with some form of cardiacdisease.11 One thing is certain:These patients are seeking lessinvasive surgeries with a short

recovery time that allows them toquickly resume their lives. Thefuture holds many exciting possi-bilities in the field of minimallyinvasive cardiac surgery. ❖

REFERENCES

1. Gao G, et al. Long-term survival ofpatients after coronary artery bypass graftsurgery: comparison of the pre-stent andpost-stent eras. Ann Thorac Surg. 2006;82:806-810.

2. Leserman J, et al. The efficacy of therelaxation response in preparing for cardiacsurgery. Behav Med. 1989;15(3):111-117.

3. Coronary artery surgery study (CASS): Arandomized trial of coronary artery bypasssurgery. Quality of life in patients randomlyassigned to treatment groups. Circulation.1983;68:951-960.

4. Bojar R. Manual of Perioperative are in AdultCardiac Surgery. Malden, Mass: BlackwellPublishing Co.; 2005.

5. Kobayashi J, Tashiro T, Ochi M, et al.Early outcome of a randomized comparisonof off-pump and on-pump multiple arterialcoronary revascularization. Circulation. Car-diovascular Surgery Supplement. 2005;112(9)(suppl):I338-I343.

6. Newman MF, Kirchner JL, Phillips-ButeB, et al. Longitudinal assessment of neu-rocognitive function after coronary-arterybypass surgery. N Engl J Med. 2001;344(6):395-402.

7. Edwards FH, Clark RE, Schwartz M. Coronary artery bypass grafting: theSociety of Thoracic Surgeons NationalDatabase experience. Ann Thor Surg. 1994;57:12-19.

8. Henneman E, Cardin S. Family-centeredcritical care: a practical approach to makingit happen. Crit Care Nurse. 2002;22(6):12-19.

9. Czibik G, D’Ancona G, Donias HW, etal. Robotic cardiac surgery: present andfuture applications. J Cardiothorac Vasc Anesth.2002;16(4):495-501.

10. Wimmer-Greinecker G, Matheis G,Dogan S, et al. Complications of Port-accesscardiac surgery. J Card Surg. 1999;14(4);240-245.

11. AHA Statistical Update. Heart Diseaseand Stroke Statistics—2007 Update. A reportfrom the American Heart Association Statis-tics Committee and Stroke Statistics Sub-committee. Circulation. 2007;115:e69-e171.

12. Smeltzer S, et al. Brunner & Suddarth’sTextbook of Medical Surgical Nursing. 11th ed.Philadelphia, Pa: Lippincott Williams &Wilkins; 2008.

Victoria A. Kark is an open heart clinical specialistat Suburban Hospital, Bethesda, Md. She is alsoan adjunct faculty member at Columbia UnionCollege, Takoma Park, Md.

The author has disclosed that she has no signifi-cant relationship with or financial interest in anycommercial companies that pertain to this educa-tional activity.

Adapted from: Kark VA. The future of minimallyinvasive cardiac surgery. OR Nurse. 2008;2(1):24-30.

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