The study of the effects of WLS on improvement and remission of hypertension (HTN) is challenging for many reasons, including the variable indications for starting antihypertensive medications such as for migraines , atrial fibrillation , and after myocardial infarction . Further, there are innumerable medications in the market and a wide range of definitions used to quantify HTN, pre-HTN, and hypertensive crisis. Additionally, “normal” values of high blood pressure may vary with age. Currently there is no standard for HTN or stage of HTN consistently used in studies of WLS . Further, there is no published randomized controlled trial (RCT) of WLS studying HTN as the primary outcome. Available research has shown varied and conflicting results: one high-quality RCT with diabetes as the primary outcome showed a significant reduction in antihypertensive medication use at 1 year without a significant change in blood pressure values [16] and a second RCT showed no benefit at 2 years [17]. Thus it is possible that the effects of WLS are more pronounced in the short term than in the long term. This differential effect of WLS on HTN with early improvement and subsequent relapse has additionally been suggested in the Swedish Obesity Subjects (SOS) study group [18]. However, this effect may vary with different surgery types, with suggestion of a high long-term rate of cure after BPD [19]. Additionally, in the absence of long-term benefit through nonsurgical means, WLS continues to be the best option with at least significant effects on medication reduction usually achieved and sustained in the short and long term [20].

Immediate Postoperative Management: Antihypertensive medications are commonly discontinued in the immediate postoperative period in many patients for various reasons including limited oral intake and increased risk of dehydration. Diuretics are thus preferably stopped. For the same reason, angiotensin-converting enzyme inhibitors are not preferred. Intravenous beta-blockers may be used based on serial monitoring of blood pressure in the immediate postoperative period. After discharge and upon resuming adequate oral intake, blood pressure should be measured weekly and medications resumed, often at lower doses.

Long-Term Management: Due to current evidence suggesting a possible relapse of HTN in the long term after WLS , patients need to be routinely followed especially in the first 2–5 years after surgery. Medication management of HTN should be tailored based on age, race, and other coexisting comorbidities including diabetes and coronary artery disease, and should be consistent with current guidelines . There are no published guidelines on the specific management of HTN in the post-WLS population. Management is based on established guidelines in adults [21].

There is a high prevalence of obstructive sleep apnea (OSA) in the severely obese patient population, ranging from 38 to 88 % [22–25]. Self-reported remission of OSA after WLS is about 60 % at 1 year but varies with age, gender, and type of surgery undergone [26]. A recent meta-analysis also found that the reduction in OSA after WLS is superior to that from nonsurgical weight loss [27]. However, data regarding resolution of OSA is plagued by underdiagnosis, lack of direct correlation between weight loss and resolution of OSA , poor compliance with recommended treatment, use of subjective and self-reported improvement as resolution, unclear guidelines on repeat testing after surgery, sparse postoperative testing data available, and a lack of RCTs [25, 28, 29]. While multiple screening tools are available, such as the Epworth sleepiness score and the Berlin questionnaire [30], none have been validated in the severely obese population. Polysomnography is the only currently valid test to determine severity of OSA. Diagnosis rests on at least five apneic or hypopneic episodes per hour. Severity is classified based on the apnea hypoxia index (AHI) or respiratory disturbance index; <5 events is normal, 5–14 is mild, 15–29 events is moderate, and ≥30 events is severe.

Preoperative Management: The management of OSA starts with appropriate testing and treatment before surgery. Patients should be seen by a pulmonologist or sleep specialist, and undergo a polysomnogram to enable the diagnosis and provide recommendations for management with continuous positive airway pressure (CPAP) . While no recommendations exist about the duration of time a patient should be on CPAP prior to surgery, optimal preparation should allow time for the patient to become accustomed to and consistently use the device.

Immediate Postoperative Management: There is no risk of increased anastomotic complications in the immediate postoperative period after gastric bypass related to use of CPAP [31]. American Society of Anesthesiology (ASA) guidelines for the general surgical population with OSA recommend continuous pulse oximetry as well as availability of an emergency airway cart in postoperative patients for at least 3 h beyond standard observation time of non-OSA patients, or for as long as obese patients are considered to be at risk [32]. In reality, postoperative monitoring of WLS patients depends on multiple factors including details of the operation, open versus laparoscopic surgery, severity of OSA, age, presence of other pulmonary disease, presence of other comorbidities, as well as capabilities at the institution. Most patients can be monitored on a general surgical floor. It may be good practice to request a respiratory therapy consultation based on institutional guidelines to optimize CPAP use, and to educate in the use of an incentive spirometer and respiratory maneuvers to decrease the risk of pulmonary events [33]. Higher risk patients may be better monitored in the critical care setting. This may include patients with a BMI greater than 60, age greater than 50, or severe OSA documented preoperatively [34, 35]. Additionally, male gender may confer a higher risk of complications requiring ICU monitoring [34, 35]. Patients using CPAP at home should continue to do so after surgery, with their own home device brought in for postoperative use in order to allow for appropriate fit and individualized settings.

Long-Term Postoperative Management: As discussed above, results regarding improvement of OSA vary based on the methods used to characterize the disease with self-reports showing greater improvement than objective testing based on polysomnogram . Based on a 2009 meta-analysis, resolution of AHI after surgery may be as high as 71 % [36]. However, the same study still showed significant residual disease with an AHI greater than 15 in 62 % of patients after surgery [36]. While short-term resolution of OSA may be as high as 83 % based on definition and follow-up methods used [37], some studies are now showing that these improvements may also be sustained long term [38]. Unfortunately, weight regain has been shown to be associated with a relapse of OSA symptoms [29, 39]. Thus it is important to consider retesting patients with weight regain after surgery , especially if they have recurrence of previously improved or resolved comorbidities. This is particularly important in the context of consideration for reoperative surgery. Again, it is important to be aware that subjective improvements in OSA may not correlate with objective improvement on polysomnographic testing, nor be predicted by significant weight loss. Thus diagnostic sleep testing should be obtained whenever possible after attaining stable weight loss or goal weight. This allows not only objective quantification of disordered sleep breathing but may also allow for retitration of CPAP , potentially increasing compliance [40].

“Dyslipidemia” and “hyperlipidemia ,” which are used interchangeably in the literature , signify abnormalities in one or more lipid subfractions in the blood. Traditionally, it is quoted that hyperlipidemia affects up to 50 % of patients with obesity, although this number has been variable in studies of patients undergoing WLS [41–43]. Multiple factors make the study of hyperlipidemia in patients undergoing surgery challenging. This includes incomplete diagnostic data, lack of unifying definitions in studies, variable number of patients on pharmacologic treatment, and significant overlap of statin use for other medical conditions including patients with diabetes mellitus , Alzheimer’s dementia , and stroke, to name a few [44]. The relationship of obesity to elevated total cholesterol (TC) , low-density lipoprotein cholesterol (LDL-C) , and triglycerides, (TG) and decreased high-density lipoprotein cholesterol (HDL-C) , has been demonstrated in epidemiological studies [45, 46]. However, while the relationship of obesity to TG and HDL-C has been affirmed in more recent studies, the relationship to LDL-C has been questioned [47]. Meanwhile studies of weight loss surgery have continued to report improvement in all lipid fractions after bariatric surgery. Of the effects noted, the increase in HDL-C has been demonstrated more consistently compared to the decrease in LDL-C [41, 48]. This is clinically significant since bariatric surgery is one of the very few interventions that can lead to an increase in HDL-C. Thus the effect of obesity and weight loss on subfractions of lipoproteins is still being studied, and reliable and replicable data on the effect of WLS is lacking. The most recent American College of Cardiology guideline (2013) for management of dyslipidemia additionally deemphasizes laboratory measurement of lipid profile to guide treatment, which might lead to incomplete data further on [49].

Perioperative Management: The American Society for Metabolic and Bariatric Surgery (ASMBS) released standard reporting guidelines for various medical conditions around the time of bariatric surgery [9]. The guideline recommended complete fasting lipoprotein profile in all patients being considered for WLS . Screening in low-risk patients with non-fasting TC and HDL was noted as a secondary option with full fasting panel if TC is greater than or equal to 200 mg/dL or if the HDL is less than 40 mg/dL. The guideline additionally recommended complete fasting lipid profile after WLS. However, it is not established when the labs should be drawn and how often should they be drawn. The improvement in lipid profile after WLS happens in the first 6 months after surgery and study has shown a sustained effect at the 2-year mark [42]. It would thus make clinical sense to draw such profiles every 6 months for the first 2 years after surgery and annually thereafter, based on the common weight loss pattern after surgery. So while patients will commonly continue their medications immediately postoperatively further adjustments should be based on laboratory follow-up. A detailed review of medication management after WLS is beyond the scope of this chapter.

Stress urinary incontinence (SUI) is commonly seen in the setting of obesity, with evidence that each five unit increase in BMI increases the risk for SUI by 20–70 % [50]. In addition, SUI disproportionately affects middle-aged and older women [51] and is therefore present to a significant degree in bariatric patients. For unclear reasons, some ethnicities are more significantly affected than others, with SUI seen more frequently in Hispanic and white women, compared to black and Asian women [51]. As with many obesity-related conditions, even modest weight loss through diet and exercise can significantly improve SUI, but by far the most dramatic effects are seen with WLS . Observational studies show a presurgical prevalence of SUI between 61 and 67 %, with a decrease to 12–37 % between 1 and 5 years postoperatively after a variety of operations [50]. Based on this, it seems unlikely that long-term management of SUI after WLS will be a significant issue for surgeons or PCPs. If it does not resolve entirely, it is likely to improve to a considerable extent and only requires ongoing lifestyle modification by the patient, as would be necessary in the lean population.

Obesity is associated with a variety of respiratory issues . Excess weight can limit chest wall compliance and decrease lung volumes, causing a restrictive ventilatory pattern and associated dyspnea on exertion [52]. This is more common with central obesity. Along with OSA and obesity hypoventilation syndrome as previously discussed, chronic obstructive pulmonary disease (COPD) is also associated with obesity and along with lower respiratory infections is currently tied as the third leading cause of death in the world [53]. In addition, asthma is more common and sometimes harder to treat in obese patients. One study showed that the prevalence of asthma was increased by 92 % in obese patients [54]. A prospective study of WLS patients showed significant improvements in asthma control and asthma-related quality of life in asthmatic patients after surgery [55]. Changes in inflammatory markers associated with asthma may be involved in such improvement, but have not yet been shown, in the small studies available, to be significantly altered after WLS. As with other obesity-related diseases , it is likely that COPD and asthma will improve or resolve after WLS, depending on the severity and associated causes of the disease process. Long-term management, therefore, is likely to be less problematic for patients undergoing WLS . Short-term management includes appropriate pulmonary toilette and use of inhalers on an as-needed basis.

Nonalcoholic fatty liver disease (NAFLD) is now the most common cause of liver disease and cirrhosis in the USA [56]. NAFLD, unfortunately, is generally asymptomatic and patients may be unaware of its presence until it is incidentally diagnosed. In addition, there is no other proven effective treatment for NAFLD beyond weight loss [57]. However, there is significant evidence of improvement of obesity-related liver disease after WLS . A systematic review and meta-analysis of 15 studies with over 700 paired liver biopsies showed that after a variety of WLSs and at different time points (2–111 months), the proportion of patients with histopathologic improvement or resolution of steatosis was 91.6 %, in steatohepatitis was 81.3 %, and in fibrosis was 65.5 % [58]. Even in patients with preoperatively diagnosed severe liver disease including cirrhosis, there are multiple studies confirming that WLS can still be safely performed [59–61]. There is every reason to expect that, like other components of the metabolic syndrome , NAFLD and its spectrum of progression are likely to improve to a great extent in patients who are able to lose significant weight through WLS . There should be no need for long-term follow-up in most patients unless they have progressed to cirrhosis. Such patients should be followed in conjunction with a liver specialist .