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1、 CHAPTER 59CONGENITAL HEART DISEASECharles D. Fraser, Jr., and Kathleen E. Carberrya parent was asked to serve as a biologic oxygenator using the technique of controlled cross-circulation; soon thereafter, the mechanical, extracorporeal, heart-lung bypass pump was devel- oped.2,3 With the aid of thi

2、s ability to support the patients circulation during intracardiac exploration, surgeons have sequentially attacked almost every described congenital cardiac anomaly. The prospect of meaningful survival for patients born with otherwise devastating congenital cardiac lesions is now expected in most, i

3、f not all, cases.As a result of this success story, there is now a large and growing population of adults with repaired or unrepaired CHD; estimates in the United States for 2005 placed the number of adult patients surviving with repaired or palliated congenitalThis chapter is designed to provide me

4、dical students, general surgery residents, and practicing general surgeons with a working tool to aid in their understanding of the features of anatomy and physiology in patients presenting for general surgical procedures in the setting of repaired or unrepaired congenital cardiac lesions. The large

5、 scope and breadth of the evolving field of congenital heart surgery precludes an exhaustive treatise on all aspects of this specialty. Several excellent and thorough textbooks of con- genital heart surgery will be referenced in this chapter, and the reader is encouraged to use them for additional i

6、n-depth under- standing of the lesions to be reviewed. Todays practicing general surgeon needs to be well versed in the basics of cardiac anatomy, physiology, and specific derangements associated with the various known congenital cardiac lesions. Furthermore, there are few patients with complex cong

7、enital cardiac lesions who may be considered cured of their cardiac problem, even after success- ful reconstructive surgery. Thus, it is imperative that th ral surgeon who needs to perform a noncardiac operation on such a patient be familiar with the specific issues of ongoing concern in those with

8、congenital cardiac disease.HISTORY AND OTHER CONSIDERATIONSThe era of surgical treatment for congenital cardiac anomalies was initiated in November 1944, when Dr. Alfred Blalock and associates Vivien Thomas and Dr. Helen Taussig combined their uniqu ents and vision to treat a young child dying of cy

9、anotic congenital heart disease (CHD).1 This palliative operation involved the surgical creation of a systemic to pulmonary artery connection in the patient suffering from inadequate pulmonary blood flow. The procedure has since been recalled as miraculous and has carried the eponym of the Blalock-T

10、aussig shunt (BT shunt) during the ensuing years, now more than 60 years later. The striking success of this simple concept and the reproducible nature of the operation in children suffering from otherwise fatal cardiac conditions has emboldened subsequent surgical innova- tors to venture inside the

11、 congenitally malformed heart. At first,s.4 This reality hascardiac lesions at more than 1 millionbeen associated with new challenges in the ongoing medicalmaintenance of such patients, with particular focus on the care of patients with congenital cardiac lesions presenting for surgery for noncardia

12、c illnesses. The evolving subspecialty of adult CHD points to the unique needs of this population of patients.PATHWAYS FOR PRACTICING CONGENITAL HEART SURGERYBefore embarking on a review of the field, it is worthwhile to describe the setting in which patients with CHD seek and receive care in todays

13、 medical environment. With the develop- ment of sophisticated methods of f ultrasound, a large per- centage of children requiring surgery for CHD are diagnosed during gestation (Fig. 59-1). Although not yet confirmed as affecting overall survival rates, a fe diagnosis of complex CHD is of inordinate

14、 help to parents and the medical management team. This is particularly important in the setting of lesions dependent on persistent patency of the ductus arteriosus for postnatal survival. In these individuals, survival after delivery is predicated on the maintenance of ductal patency through the IV

15、infusion of prostaglandin E1 (PGE1) initiated in the delivery suite, often through an umbilical vein catheter.A growing number of congenital cardiac lesions is known to be associated with specific genetic mutations, many clearly inherited and some presumed to be sporadic. As such, a chro- mosomal an

16、alysis is frequently performed in those found to have major structural cardiac abnormalities; this analysis may be per- formed during gestation through an amniocentesis. The chro- mosomal evaluation is of benefit to the family when planning the risk of such an occurrence in future offspring. For the

17、 clini- cian, knowledge of chromosomal abnormalities in their patients, such as DiGeorge sequence, velocardiofacial syndrome, and1611history and other considerations anatomy, terminology, and diagnosis perioperative carelesion overview single ventriclemiscellaneous anomalies summary1612 SECTION XI C

18、HESTthe general surgeon faced with operating on an adult patient with significant CHD. One overriding message needs to be clearNormal f4-CLVHLHSto teral surgeon in this setting: it must be assumed thatin patients with previously repaired congenital cardiac lesions,even without overt cardiac symptoma

19、tology, the potential for significant perioperative cardiorespiratory derangement exists. More simply stated, the presence of a surgical scar on the chest of a patient wit own CHD does not suggest that the lesion has been cured. With this firmly in mind, th ral surgeon may find it challenging to det

20、ermine the best source for a quali- fied consult for such a patient. At present, many adult cardiol- ogists are not adequately trained in CHD to be expected to provide competent consultation on adult patients with CHD.On the other hand, pediatric cardiologists are not educated in adult medicine and

21、cardiology; many feel uncomfortable providing consultation on adult patients with CHD. As noted, the subspecialty of adult CHD is still in a state of development but, at present, there are few physicans who have been educated specifically to care for these patients. This underscores the necessity of

22、 the practicing general surgeon to become familiar with the specific issues of concern for patients with CHD to ascertain that the patients unique anatomic and physiologic issues have been evaluated properly. Adult patients with CHD who present for care in a center without a designated qualified spe

23、cialist must be evaluated by a pediatric cardiologist in coordination with an adult cardiologist. Of equal importance, the anesthesiologists and intensivists caring for such a patient must have a working understanding of the complexities and nuances of the patients cardiac condition.6 The anesthetic

24、 man- agement of patients with CHD undergoing general surgical procedures is complicated and can become disastrous if managed improperly.ANATOMY, TERMINOLOGY, AND DIAGNOSISAnatomy and TerminologyOne of the most intimidating aspects for the student of CHD is developing a level of comfort with the ter

25、minology used for describing specific lesions. To begin, a thorough and sound understanding of normal cardiac anatomy is mandatory. There are several excellent texts on this subject; in particular, the one edited by Wilcox and coworkers7 is especially concise and clear. One difficulty that challenge

26、s proper understanding of anatomy is the frequent use of abbreviations and eponyms for various congenital lesionsfor example, congenitally corrected transpo- sition of the great arteries (ccTGA), ventricular inversion, and L-transposition all describe the same heart, but none provides a complete ana

27、tomic description. Unless otherwise clear to all involved in the care of these complicated patients, the anatomic description needs to be segmental and complete to avoid mis- takes and misinterpretations of structure.In describing congenital cardiac lesions, a segmental approach is used to determine

28、 the relationship of the various structural elements. The situs describes the relationship of sidednesssitus solitus (normal), situs inversus (reversed), or situs ambiguous (indeterminate). The cardiac elements described include (in sequence) the atria, ventricles, and great vessels. The relationshi

29、p of the connections must be understood; connec- tions are concordant (e.g., right atrium connecting to right ventricle) or discordant (e.g., right ventricle connecting to the aorta). The chamber sidedness must be clarified (e.g., aMVLVFIGURE 59-1 Normal fultrasound (four chamber; left) and fultraso

30、und of a child with HLHS (right). LV, Left ventricle; MV, mitral valve.Marfan syndrome, aids in the delivery of acute medical management.In general terms, the timing of surgery for various congeni- tal cardiac conditions depends on the presenting symptomatol- ogy and expectations for further associa

31、ted complications. Children presenting with limited pulmonary blood flow or atretic pulmonary connections typically require surgery during the first few days of life and occasionally within hours of delivery. Lesions associated with excessive pulmonary blood flow result in early heart failure, which

32、 may manifest as poor feeding, tachypnea, or even respiratory failure. These patients are oper- ated on during early infancy to ameliorate their symptoms and prevent the development of pulmonary vascular disease.Preterm and low-birth-weight babies with CHD have been presenting for surgical considera

33、tion with more frequency. This treatment strategy requires thoughtful planning and coordina- tion among the surgery, anesthesia, cardiology, intensive care, and neonatology teams. Recently, at our institution, the Texas Childrens Hospital, we successfully operated on an 800-g baby with transposition

34、 of the great arteries (TGA).The specialty of congenital heart surgery is now recognized as a subspecialty of cardiothoracic surgery. Congenital heart surgeons were previously certified in cardiothoracic surgery by the American Board of Thoracic Surgery (ABTS) and received additional fellowship trai

35、ning in the United States or abroad in congenital heart surgery. As of 2009, the ABTS offers a formal certification process for subspecialty training in Congenital Heart Surgery. At this time, there are 10 congenital cardiac surgery residency programs approved by the Accreditation Council for Gradua

36、te Medical Education. Most pediatric cardiac surgery is performed in large, multispecialty childrens hospitals in association with formal programs focused on the care of these complex patients. The management team includes pediatric cardiac anesthesiologists, perfusionists, and nursing staff. Focuse

37、d pediatric cardiac intensive care units have been devel- oped to optimize the patients opportu for recovery.Historically, pediatric cardiologists have provided the medical management of patients born with CHD. Pediatric cardiology is also evolving. With advances in catheter-based technology, lesion

38、s previously treated with surgery are now being addressed by interventional pediatric cardiologists. Examples include device closure of atrial and ventricular septal defects (VSDs), occlusion of patent ductus arteriosus (PDA), and dila- tion and stenting of stenotic vessels in the systemic and pulmo

39、- nary circulation. For a more in-depth recent review of this specialty, see the excellent technical text by Mullins.5The situation of care for adults with CHD is not as well organized as for children. This issue is of particular relevance toCoNgENiTaL HEarT DiSEaSE ChapTEr 59 1613"NORMALS"

40、;SD SAoLATVPARARV1Situs solitusASitus inversusLVRLMVPdepicting cardiac morphology for normalFIGURE 59-3 Congenitally corrected transposition of the great arter- ies. atrial situs solitus (normal) with atrioventricular discordance and ventriculoarterial discordance using anderson nomenclature, S,L,L

41、by Van Praagh classification. Ao, aorta; La, left atrium, LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle; TV, tricuspid valve.FIGURE 59-2 Mheartsthat is, hearts with atrioventricular concordance and ventricu- loarterial concordance using Van Praagh nomenclature. The vert

42、ical line above the box denotes the position of the ventricular septum. (From Kirklin JW, Barratt-Boyes Bg: general considerations: anatomy, dimensions, and terminology. in Kirklin JW, Barratt-Boyes Bg: Cardiac surgery, ed 2, New York, 1993, Churchill Livingstone.)necessity of a thorough history and

43、 physical examination. Most patients who have a history of CHD become very well informed about the specifics of their cardiac conditions, as do their parents. A detailed review of the patients past medical history is abso- lutely mandatory. This includes, when possible, securing records from all pre

44、vious diagnostic and procedural reports. It is disturb- ing how often an incorre sumption is made about a patients previous surgical history and anatomy, frequently in a setting in which a patients old operative report or clinical summary could easily clarify the misunderstanding.In adults with CHD,

45、 in particular, there are specific points of medical history that must be elucidated. A history of palpita- tions, syncope, and neurologic deficit must be further investi- gated. The incidence of significant dysrhythmias in certain categories of adults with CHD is high and, in many cases, war- rants

46、 further investigation, including continuous monitoring (Holter), electrophysiologic study, and/or provocative testing.Physical ExaminationA complete physical examination in a patient with previously repaired CHD will often yield information critical to the proper planning of a general surgical proc

47、edure. Patients need to be completely undressed and thoroughly examined. In many cya- notic patients, color changes may be prominent, particularly in the nail beds, lips, and mucous membranes. In other patients, cyanosis may be subtler, giving the patient a gray or even pale appearance. Previous sur

48、gical incisions need to be noted and reconciled with the known medical history. Thoracotomy inci- sions on either side may indicate a previous BT shunt using the turned-down, divided subclavian artery or with a prosthetic interposition graft, the so-called modified BT shunt. In patients with a left

49、aortic arch, a left thoracotomy incision will be present if a previous coarctation repair has been carried out. Median sternotomy incisions or anterior thoracotomy incisions may indicate previous intracardiac or extracardiac surgery.A complete vascular examination is often overlooked in patients wit

50、h CHD. It is important to assess pulses and obtain blood pressure measurements in all four extremities. Patients who have an existing or have previously had a BT shunt often have diminished or absent pulses in the upper extremity corre- sponding to the previous shunt. This may also be true in the le

51、ftmorphologic right atrium may be on the left side of the patient). The relationship and connections of the cardiac valves must then be assessed; connections may be normal, stenotic, atretic, orstraddling. Of note to teral surgeon, abnormal sidednessof the cardiac structures is frequently associated

52、 with abnormal relationships of the thoracic and abdominal organs. A thorough assessment of the patients anatomy is recommended before surgery.There are two widely accepted and applied schools of cardiac morphologic description. The Van Praagh nomenclature uses abbreviations to describe the relation

53、ship of the atria, ven- tricular looping, and position of the aorta sequentially. The first letter describes the situs of the atrial chambers (and usually the abdominal organs): S for situs solitus (normal), I for situs inver- sus (reversed), or A for situs ambiguous (indeterminate). The second lett

54、er describes the relationship of the embryologiclooping of the ventricles; D for dextro looping or right-handed topology (normal) or L (levo) for left-handed topology. The third and last letter describes the relationship of the aortic valve to the pulmonary valve, D for right-sided and L for left-si

55、ded (Fig. 59-2).The Anderson nomenclature is more wordy and longer, but is perhaps simpler to understand. The descriptions are again of the sequential relationship of the structures. Starting with the atria, the connections and relationships are sequentially described. Thus, the atrial sidedness is

56、described, followed by the sequence of connections to the ventricles and then great vessels. For example, atrial situs solitus (normal) with atrioventricular discordance (reversed) and ventriculoarterial dis- cordance (reversed) describes the heart mentioned earlier as cor- rected transposition, or

57、S,L,L by the Van Praagh classification (Fig. 59-3).DiagnosisAs with all aspects of surgery, there is a wide variety of highly sophisticated diagnostic tools available to examine cardiac struc- ture and function. Despite the widespread availability and appli- cation of these tools, none has replaced

58、or eliminated theSECTION XI CHESTIsolated ventricular inversionSILDSIIL I234LV RVLA RARVLVLARALVRVRALARV LVRA LA1614 SECTION XI CHESTupper extremity in patients with previous coarctation repairs, especially if a subclavian flap angioplasty was performed (Wald- hausen procedure). Furthermore, a histo

59、ry of previous coarcta- tion repair does not guarantee that the lower extremity pulses and blood pressures will be normal. Also, patients who have undergone previous cardiac catheterization may have chronically stenosed or occluded femoral vessels. All these issues may be of significance for monitoring and vascular access in a pa